This patch adds new method for retrieving of default properties of enrol_self instances and uses it both for automatic adding of instances and add instance form - this will guarantee both are using the same data in the future.
This commit coverts everything in the codebase to use the new
users_order_by_sql function when sorting lists of users. More details in
the bug.
Note that this does not change places where users are displayed in a
sortable table, and the sort order comes from the table.
Includes option to convert all enrolments to enrol_manual instances, support for mapping of custom fields and fixes for several other problems. This does not include support for custom enrol tables, it will be addressed in another issue.