Rate limit joins per-room (#13276)

changelog.d/13276.feature

docker/complement/conf/workers-shared-extra.yaml.j2

docs/upgrade.md

docs/usage/configuration/config_documentation.md

synapse/config/ratelimiting.py

synapse/federation/federation_server.py

synapse/handlers/federation_event.py

synapse/handlers/message.py

synapse/handlers/room_member.py

synapse/replication/tcp/client.py

synapse/replication/tcp/streams/events.py

synapse/storage/databases/main/events_worker.py

tests/federation/test_federation_server.py

tests/handlers/test_room_member.py

tests/rest/client/test_rooms.py

tests/test_server.py

tests/unittest.py

tests/utils.py