Groups can end up with no admins and/or no members at all

[Robert Lyon]

When a user is deleted they are removed from any groups they belong - but there is no check to see if they are the only admin member of the group (or even the only member).

There needs to be some logic around this

When self deleting:
-------------------
- Delete (or warn about) all groups they are the only member of
- Warn about all groups that have them as only admin member (but have other members) and give them a chance to assign another member to be group admin

When deleting user as admin:
----------------------------
- Warn if the user is only member or only admin of groups to allow admin to assign new admin(s) / member(s)

[Robert Lyon (robertl-9)]

There will also need to be some thought about how to deal with existing groups
- that are rudderless, that is have no admins
- that have been abandoned, that is have no members

[Robert Lyon (robertl-9)]

Having a group with no admin/members is not necessarily a bug as a site admin can always add a user to a group as a group admin via Administration -> Groups -> Administer groups -> Manage (cog) button.

[Kristina Hoeppner (kris-hoeppner)]

Robert and I discussed it in person. Since account deletion only affects personal data and not collaborative data, I'd not tie the group deletion to the account deletion as that might get messy from an institution standpoint. An institution may want to keep the data there even if there aren't any group members.

What we propose for this wishlist item:

1. Make columns in Admin -> groups -> Administer groups sortable so that we can sort for the number of admins and group members. Ideally, all columns will be sortable and not just these two.

2. When the last admin left a group and there are still other members in the group, send an email to the institution admin (or site admin if there is no institution admin or the group is under "No institution) and let them know that the group doesn't have an admin and if they wanted to appoint a new one.

3. When the last admin left a group and was the last member, send an email to the institution admin (or site admin if there is no institution admin or the group is under "No institution) and ask if they want to delete the group.