MDL-53081 docs: Improve the text doc files in the root directory

Existing contents of README moved to INSTALL. Added new README,
CONTRIBUTING and PULL_REQUEST_TEMPLATE files. TRADEMARK updated using
the text at https://moodle.com/trademarks/.

CONTRIBUTING.txt

+CONTRIBUTING TO MOODLE
+======================
+
+Moodle is made by people like you. We are members of a big worldwide community
+of developers, designers, teachers, testers, translators and other users. We
+work in universities, schools, companies and other places. You are very welcome
+to join us and contribute to the project.
+
+See <https://docs.moodle.org/dev/Contributing_to_Moodle> for the many ways you
+can help, not only with coding.
+
+Moodle is open to community contributions to core, though all code must go
+through peer-review, automated behaviour testing, continuous integration and
+human post-integration checks.
+
+Pull requests
+-------------
+
+Please do not open pull requests via Github. The repository there is just a
+mirror of the official repository at <https://git.moodle.org>. Issues are
+reported and patches provided via <https://tracker.moodle.org>. See below for
+more information.
+
+Moodle core bug fixes and new features
+--------------------------------------
+
+During the years of intensive development, a mature process of including
+submitted patches has evolved.
+
+* Every bug fix or new feature must have a tracker issue.
+* You publish the branch implementing the fix or new feature in your public
+  clone of the moodle.git repository (typically on Github).
+* Your patch is peer-reviewed, discussed, integrated, tested and then released
+  as a part of moodle.git.
+* New features are developed on the master branch. Bug fixes are also
+  backported to currently supported maintenance (stable) branches.
+
+For further details, see <https://docs.moodle.org/dev/Process>.
+
+Moodle plugins
+--------------
+
+Moodle has a framework for additional plugins to extend its functionality. We
+have a Moodle plugins directory <https://moodle.org/plugins/> where you can
+register and maintain your plugin. Plugins hosted in the plugins directory can
+be easily installed and updated via the Moodle administration interface.
+
+* You are expected to have a public source code repository with your plugin
+  code.
+* After registering your plugin in the plugins directory it is reviewed before
+  being published.
+* You are expected to continuously release updated versions of the plugin via
+  the plugins directory. We do not pull from your code repository; you must do
+  it explicitly.
+
+For further details, see <https://docs.moodle.org/dev/Plugin_contribution>.

INSTALL.txt

+MOODLE INSTALLATION
+===================
+
+Here is a short summary of the installation process (which can take just a few
+minutes):
+
+1. Move the Moodle files into your web directory.
+
+2. Create a single database for Moodle to store all its tables in (or choose an
+   existing database).
+
+3. Visit your Moodle site with a browser. You should be taken to the
+   install.php script, which will lead you through creating a config.php file
+   and then setting up Moodle, creating an admin account etc.
+
+4. Set up a cron task to call the file admin/cron.php every minute.
+
+For more information, see <https://docs.moodle.org/en/Installing_Moodle>.
+
+Good luck and have fun!

PULL_REQUEST_TEMPLATE.txt

+*** PLEASE DO NOT OPEN PULL REQUESTS VIA GITHUB ***
+
+The moodle.git repository at Github is just a mirror of the official repository. We do not accept pull requests at Github.
+
+See CONTRIBUTING.txt guidelines for how to contribute patches for Moodle. Thank you.
+
+--

README.txt

-QUICK INSTALL
-=============
+                                 .-..-.
+   _____                         | || |
+  /____/-.---_  .---.  .---.  .-.| || | .---.
+  | |  _   _  |/  _  \/  _  \/  _  || |/  __ \
+  * | | | | | || |_| || |_| || |_| || || |___/
+    |_| |_| |_|\_____/\_____/\_____||_|\_____)
 
-For the impatient, here is a basic outline of the
-installation process, which normally takes me only
-a few minutes:
+Moodle - the world's open source learning platform
 
-1) Move the Moodle files into your web directory.
+Moodle <https://moodle.org> is a learning platform designed to provide
+educators, administrators and learners with a single robust, secure and
+integrated system to create personalised learning environments.
 
-2) Create a single database for Moodle to store all
-   its tables in (or choose an existing database).
+You can download Moodle <https://download.moodle.org> and run it on your own
+web server, ask one of our Moodle Partners <https://moodle.com/partners/> to
+assist you, or have a MoodleCloud site <https://moodle.com/cloud/> set up for
+you.
 
-3) Visit your Moodle site with a browser, you should
-   be taken to the install.php script, which will lead
-   you through creating a config.php file and then
-   setting up Moodle, creating an admin account etc.
+Moodle is widely used around the world by universities, schools, companies and
+all manner of organisations and individuals.
 
-4) Set up a cron task to call the file admin/cron.php
-   every five minutes or so.
+Moodle is provided freely as open source software, under the GNU General Public
+License <https://docs.moodle.org/dev/License>.
 
+Moodle is written in PHP and JavaScript and uses an SQL database for storing
+the data.
 
-For more information, see the INSTALL DOCUMENTATION:
-
-   http://docs.moodle.org/en/Installing_Moodle
-
-
-Good luck and have fun!
-Martin Dougiamas, Lead Developer
-
+See <https://docs.moodle.org> for details of Moodle's many features.

TRADEMARK.txt

-------------------------
-Moodle Trademark License
-------------------------
-
-The name Moodle™ is a registered trademark of the Moodle Trust.
-
-A key part of the business model that allows us to produce and
-distribute Moodle as completely Free open source software is that
-we restrict the commercial use of the Moodle trademark to those
-who have contracted to support Moodle development (Moodle Partners).
-
-If you are intending to use the name (and/or logo) to advertise
-generic Moodle™ services (eg Moodle Hosting, Moodle Support,
-Moodle Certification, Moodle Training, Moodle Consulting,
-Moodle Customisation, Moodle Courseware Development, Moodle
-Theme design, Moodle Integrations, Moodle Installations, etc)
-or as the name of a software package, then you must seek
-direct permission in writing from the Moodle Trust via the
-moodle.com helpdesk, in accordance with normal trademark
-restrictions.
-
-There are no restrictions on how you use the name in other
-contexts (for example, if you use Moodle just to provide
-courses then you can use the name freely to refer to it.)
-
-If you aren't sure of a particular case, please ask us via
-http://moodle.com/helpdesk: we'll be happy to either provide
-you with official permission in writing or help you fix
-your wording.
-
-Martin Dougiamas
-Executive Director
-Moodle Trust
-http://moodle.com
+MOODLE TRADEMARKS POLICY
+========================
+
+The word "Moodle" is trademarked in many countries around the world. The word
+was originally an acronym: Modular Object-Oriented Dynamic Learning
+Environment. The trademark is owned by Martin Dougiamas, Founder and Director
+of Moodle.
+
+The law obligates trademark owners to police their marks and prevent the use of
+confusingly similar names by third parties. Through this policy we’d like to
+make it clear how Moodle-related projects, organisations, and people can use
+the Moodle trademark. We’d also like to be clear about how use of the word is
+restricted when used to promote commercial Moodle services. We do this to
+protect the very business model that allows us to continue developing Moodle
+for you.
+
+Allowed uses
+------------
+
+The following uses don’t require any permission at all:
+
+* Referring to the software or the Moodle project.
+* Describing your own Moodle implementation (including within corporate
+  settings).
+* Describing a Moodle-based community hub.
+* Describing some software you’ve made that integrates with Moodle
+  (eg a Moodle integration feature on another system).
+
+Restricted uses
+---------------
+
+The following uses are generally prohibited without explicit and direct
+permission being granted to you by Moodle Pty Ltd. We do this to protect the
+Moodle project from software and sites which could confuse people. Please
+contact us to ask for permission in writing.
+
+* You can’t use "Moodle" in the name of your software (including Mobile apps)
+* You can’t use "Moodle" in your company name
+* You can’t use "Moodle" in your domain name
+* You can’t use "Moodle" in advertising-related keywords (such as Adsense)
+* You can’t use "Moodle" to describe services around Moodle (such as hosting,
+  training, support, consulting, course creation services, theme development,
+  customisation, installation, integration and certification). This applies
+  even if you do not charge for the services. Note that usually only Moodle
+  Partners have this permission.
+
+For information about the Moodle Partner Certification Mark as well as for how
+to contact us, please see <https://moodle.com/trademarks/>.