Reduce the amount of state we pull from the DB (#12811)

changelog.d/12811.misc

synapse/api/auth.py

synapse/federation/federation_base.py

synapse/federation/federation_server.py

synapse/handlers/directory.py

synapse/handlers/federation.py

synapse/handlers/federation_event.py

synapse/handlers/initial_sync.py

synapse/handlers/message.py

synapse/handlers/room.py

synapse/handlers/room_member.py

synapse/handlers/search.py

synapse/notifier.py

synapse/rest/admin/rooms.py

synapse/rest/client/room.py

synapse/server_notices/resource_limits_server_notices.py

synapse/state/__init__.py

synapse/storage/controllers/state.py

tests/federation/test_federation_server.py

tests/handlers/test_directory.py