Filter by enrolment methods when adding members to groups

In order to help users add or remove members in a group, it would be a good idea to integrate an enrolment methods filter.
The main idea of this improvement is to make it easy to add users from a specific course meta link. See attachment picture for example in the interface.

Groups and course meta links enrolments are a big concern to our users and right now there's no easy way (In fact it's a pretty hard way) to create a group that is based on them.

We are about to integrate a patch to add this feature in our Moodle and I'll post it shortly in github.