Merge remote-tracking branch 'origin/develop' into rav/refactor_accesstoken_delete

synapse/federation/transport/client.py

synapse/federation/transport/server.py

synapse/groups/groups_server.py

synapse/handlers/auth.py

synapse/handlers/device.py

synapse/handlers/groups_local.py

synapse/rest/client/v1/login.py

synapse/rest/client/v2_alpha/groups.py

synapse/rest/client/v2_alpha/register.py

synapse/storage/group_server.py

synapse/storage/registration.py

synapse/storage/schema/delta/23/refresh_tokens.sql

...pse/storage/schema/delta/33/refreshtoken_device_index.sql

synapse/storage/schema/delta/46/drop_refresh_tokens.sql

tests/storage/test_registration.py