* Move it under the discussion column.
* Change it to look like a label
* Plus limit the group name to 15 characters
* Plus some accessibility fixes:
- Add labels to column headings.
- Set discussion name as a row heading.
* Remove striped table row style
* Move subscribe icon to the action menu
* Update the action menu icon
* Remove the Last post column
* Removed the "Created" column and moved the date under "Started by"
* Added "Locked" and "Subscribed" indicators under discussion names.
* Added group name with the group picture. For groups without pictures,
a default placeholder picture is now shown.
* This is how the usual moodle action menu is built.
* Removed the 'type="button"' attribute as it is not necessary.
* Added template context so it renders in the template library.
The default size for the stored file icon was only 16px by 16px which
wasn't suitable for display in the new forum layout. I've increased
the default size to 128px by 128px so that it looks better scaled up.
Added some classes to reset the content styling to a flatter
look and fix the content width.
Also fixed up the toggle styling which was previously broken.
To take advantage of native accessibility features of lists such as counting
the number of items in the list for screen readers, the nav menu should
wrap it's links in unordered list markup.
This lets plugins other than activity modules backup and restore
question attempt data.
The old backup_questions_activity_structure_step and
restore_questions_activity_structure_step base classes still exist
and work exactly the same way they did before (because they use the
trait) so this change is completely backwards compatible.
To make this work fully, a few other things in the code had to be tweaked:
* Adding restore path elements had to consider the possibility of grouped
parents in more places.
* I needed to add protected get_task() to the restore_plugin class.
I don't think that is a problem.
* In the restore trait, the process_question_... methods needed to be
changed to public for some reasons to do with PHP traits that I don't
fully understand. However, I don't think this change is a problem.
* The way question_usage restore got the new contextid had to be changed
(or it did not work in activity contexts), but the new code looks like
a better way to do it anyway so that is good.
