[Feature request] A lesser IP ban

Context This feature would help deal with people trying to annoy others on the server.

Describe the feature you have in mind Reposting my idea from #1655 (discussion of ban types):

I'd like to ban IPs not entirely but "just" from using features that annoy others. I imagine a severely restricted mode as default ban, e.g. from that IP we only accept one new user every 3 minutes, and we accept only chat messages, no voice. Originally I thought of limiting TCP connections, but abuse on that level should instead be handled by firewall rules.

Possible feature creep:

• Finding a nicer name for this feature.
• Approve certificates to exempt their users from these restrictions.
• Exempt users that authenticate with the supw.
• Restrict subnets by custom prefix length. (default = 24 bits?)
• Pick a less restrictive mode if (or as soon as) there are more than (number) clients with voice privilege currently connected from that IP.
• Confine the restricted users to a certain room, or possibly auto-create a room with a default name if none is configured for this purpose.
• Check if users may need help managing their notifications to minimize potential annoyances from restricted users, but still be notified enough in case they might want to review their chat messages.

Describe alternatives you've considered

• Traditional on/off banning
• Ban appeal via non-mumble channels, which may cause unnecessary problems with discoverability and/or privacy.
• VPN or other tunnels for approved users => additional latency.

Additional context The locked thread is missing the use case of NAT in non-family shared housing like dorms or hostels, where it may be unpractical to determine the person who might have caused the ban, and might be impossible to convince them in a timely manner. Another example of accumulation of same server's users may be a convention for a certain game, with opposing teams settling in the same hostel.