perm: Allow adding groups with some uppercase letters with `trac-admin $ENV permission add`, and prevent creating all-uppercase users and groups.
perm: Allow adding groups with some uppercase letters with `trac-admin $ENV permission add`, and prevent creating all-uppercase users and groups.

Closes #9279.


git-svn-id: 0d96b0c1a6983ccc08b3732614f4d6bfcf9cbb42@9593 af82e41b-90c4-0310-8c96-b1721e28e2e2

rbaumg/trac,rbaumg/trac,rbaumg/trac,rbaumg/trac