Use a more specific label for adding moderators
The label is now based on the active authentication providers:
- "E-mail": if only the internal user DB is enabled (and guest users)
- "User": in all other cases
In the German l10n "Benutzerkennung" (which could be a username or an e-mail address) is used but the English equivilant "User ID" could be confused with our internal user ID, so I think using just "User" is better here.
In practice these changes mean, that only "E-mail" is shown for particify.de and "User" is shown for setups with SSO authentication.
Edited by Daniel Gerhardt