馃悰 [Bug] the slug of a user must be unique
Created by: Tirokk
Authored by ogerly
馃悰 Bugreport
the user slug should either be restricted or best locked for modification.
Expected behavior
the slug should not be changeable. a change can be submitted. the slug is like a unique id. it must not be possible for a user to change his slug without problems. the username can always be changed at the moment. also here i would set a lock of a time period.
to make fake accounts a bit harder to live with, it is necessary to save the slug as well as the id permanently. id and slug can never be changed by a user.
the slug can be requested for change by a request via the moderation level