Add support to mobile testing
The following settings have been added to the Task:
- mobileVersion to choose the Moodle app version to run the behat tests with the @app label
- installLocalMobile to decide whether the local_mobile plugin has to be installed from the official GIT repo (branch MOODLE_37_STABLE). The local_mobile plugin includes some extra behat tests for the app.
- pluginsToInstall to add support to the PLUGINSTOINSTALL variable, to let deploy external plugins into the Moodle site.