Add `rooms.room_version` column (#6729)

changelog.d/6729.misc

synapse/federation/federation_client.py

synapse/handlers/federation.py

synapse/handlers/room.py

synapse/rest/client/v2_alpha/room_upgrade_rest_servlet.py

synapse/storage/data_stores/main/room.py

...data_stores/main/schema/delta/57/rooms_version_column.sql

synapse/storage/data_stores/main/state.py

tests/storage/test_room.py

tests/storage/test_state.py

tests/utils.py