* A method to change the max mark for one question_attempt in the usage

* A method to replace one question in a usage with another, moving the
old question_attempt to the end.

* Methods to set and get metadata (string name value pairs) for each
question_attempt in the usage. This gets stored in the first step in a
way that should not interfere with anything else.

There are several improvements over what we had before:

1. We track all the questions seen in the the student's previous
quiz attempts, so that when they start a new quiz attempt, they get
questions they have not seen before if possible.

2. When there are no more unseen questions, we start repeating, but
always taking from the questions with the fewest attempts so far.

3. A similar logic is applied with variants within one question.

There is lots of credit to go around here. Oleg Sychev's students Alex
Shkarupa, Sergei Bastrykin and Darya Beda all worked on this over
several years, helping to clarify the problem and shape the best
solution. In the end, their various attempts were rewritten into this
final patch by me.

Signed-off-by: Yuliya Bozhko <yuliya.bozhko@totaralms.com>

We have tests that depends on it and it
is a simple repo that can just be disabled.

Fix restore to support old criteria not having descriptions.
Plus delete not-needed cast (now $params is always already array).

Conflicts:
	lib/editor/atto/yui/build/moodle-editor_atto-editor/moodle-editor_atto-editor-min.js