Restrict community creation to instance administrators

(#1370) Feature Under consideration community self-hosting

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Comment by @snappyapple632
RexSystem 1 vote edited originally by @snappyapple632 on GitHub
This is another point I wanted to add to my own discussion #1372. For larger, general purpose instances, this would be essential, lest we have to use our own scripts to autodelete any non-whitelisted communities.