Add Group Admin assignments to User's Personal Settings (alongside their Group membership) in WebGUI

In the WebGUI add "Groups for which the user is a Group Admin" to the user's Personal settings dialog. Users access that dialog by clicking the Settings option in the top right dropdown menu or by taking a URLs like:-
https://SOMESERVER.xxx/index.php/settings/user

The existing Personal Settings dialog does include the list of Groups for which the user is a member. So to extend to include groups where they are Group Admins is logical. The info is not available anywhere else which is accessible to a User (except by viewing the items in a dropdown box in the modify User dialog, not at all intuitive)

Note: Group Admin is synonym for Subadmin:- Most of the user facing items in webGUI refer to"Group Admins". Note though that much of the internal code refers to "Subadmins".

Context: How we user NextCloud Group Folders, Groups, Group Admins

Our (non-profit) organisation uses the Group Folders functionality to control access - users need to be members of particular groups to get read or write to particular areas. Maintenance of Group membership is carried out by those set up as Group Admins who can add and remove users from the Group(s) they control. This provides an efficient delegation of access control activities to the right level.

Start at the WebGUI Personal Settings dialog reached through the top-right Settings menu or /index.php/settings/user, and compare it with the modify User dialog where Group Admin assignments are currently visible. Add a clearly labeled list of groups for which the user is a Group Admin alongside group membership, then verify the information is shown for applicable users.