Merge branch 'develop' into babolivier/acme-delegated

UPGRADE.rst

changelog.d/4643.misc

changelog.d/4647.feature

changelog.d/4657.misc

synapse/config/key.py

synapse/config/room_directory.py

synapse/crypto/keyring.py

synapse/groups/attestations.py

synapse/handlers/device.py

synapse/handlers/directory.py

synapse/handlers/groups_local.py

synapse/storage/state.py

tests/config/test_room_directory.py

tests/handlers/test_directory.py