Merge branch 'develop' of https://github.com/matrix-org/synapse into release-v0.27.0

UPGRADE.rst

docs/workers.rst

scripts/synapse_port_db

synapse/api/errors.py

synapse/app/homeserver.py

synapse/app/synctl.py

synapse/federation/transport/client.py

synapse/federation/transport/server.py

synapse/groups/groups_server.py

synapse/handlers/device.py

synapse/handlers/e2e_keys.py

synapse/handlers/groups_local.py

synapse/handlers/identity.py

synapse/handlers/message.py

synapse/http/matrixfederationclient.py

synapse/http/server.py

synapse/replication/tcp/commands.py

synapse/rest/client/v1/room.py

synapse/rest/client/v2_alpha/groups.py

synapse/state.py