allow groups to be member or admin of other groups

[KiaraGrouwstra]

Is your feature request related to a problem? Please describe.
our organization has teams administering other teams, tho not administering the entire server.
therefore, it would seem desirable to let people of the super-team administer the sub-teams and their members.
as the members of the super-team may change tho, it would seem desirable to assign these rights on the level of the super-group, rather than of its individual members.
however, as it stands, it seems only individual users may be assigned member or admin status in a group, whereas other groups may not.

Describe the solution you'd like
allow groups to be member or admin of other groups

Describe alternatives you've considered
giving the super-team their own instance of stuff they administer, and apply some federative relationship with the original instance such that super-team members don't get too many rights over others.

Additional context
relationships between entities of the same type (in this case: groups) seems like the kind of thing generally tackled using graph databases rather than relational ones. as such, solving this without architectural adjustments may be non-trivial.