Allow non-admin users to see groups' members

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Is your feature request related to a problem? Please describe.
We have a rather big Nextcloud instance where we use group to model the organization's organisational structure. However, users don't know who is in which group. Some users are unsure who they share files, links, calendars, etc with when they share them with a group. Therefore, it would be nice if a user had the chance to find out who is a member of a certain group, and which groups a certain user is a member of.

Describe the solution you'd like

• Add groups to the contacts search to the top right, and add group pages analogous to user pages (/u/userid). On group pages, show the members of the group, and on user pages, add a list of groups that user is a member of.
• In the sharing dialog, add member-lists to group. I don't exactly know how to design this (especially for larger groups), but it would be nice if users didn't need to leave the sharing dialog to get this information. Maybe also add this to the contacts search on the top right for quick access.

Describe alternatives you've considered

• We are considering implementing a script which would compile such an overview as a file which would be shared with every user. This solution is not perfect, but better than users not having this information at all.
• Circles aren't an option because we explicitly want these groups to be set up by admins/ldap, and not by users directly. We are also using group folders.

Additional context

• Add privacy options which can be set by administrators for the nextcloud instance, because in some use-cases this kind of visibility might not be appropriate. The settings could be: Disable this function alltogether, allow users to see members of their own groups only, allow users to see members of all groups. In the own-groups-only case, also hide the respective groups from user pages.

Start by tracing the contacts search, user pages at /u/userid, and the sharing dialog to identify the existing user and group visibility flows. Define how group pages, user group lists, sharing-dialog member lists, and administrator privacy settings should behave, then verify the behavior for each proposed visibility mode.