Invitation code as a prerequisite for registration

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Feature request

Which Nextcloud Version are you currently using: (see administration page)
30.0.4

Is your feature request related to a problem? Please describe.
If the app is activated, basically anyone can register, which can mean a lot of work for the administrator.

Describe the solution you'd like
In order to restrict registration to authorized groups of people, it would be helpful if the administrator could create invitation codes in advance and make them available to those authorized. These invitation codes should be restricted to both one-time and time-limited use.

Describe alternatives you've considered
-/-

Additional context
-/-

Start by reviewing the registration app's existing registration flow and administrator configuration to identify where registration access is controlled. Define how administrators create invitation codes and how one-time and time-limited use should be enforced. Done means authorized users can register with valid codes while expired, reused, or invalid codes are rejected.