Merge remote-tracking branch 'origin/develop' into rav/event_auth/1

CHANGES.md

changelog.d/6196.misc

changelog.d/6197.docker

changelog.d/6212.bugfix

changelog.d/6216.bugfix

contrib/docker/README.md

contrib/docker/docker-compose.yml

debian/changelog

docker/conf/log.config

scripts/synapse_port_db

synapse/__init__.py

synapse/config/logger.py

synapse/handlers/presence.py

synapse/rest/admin/__init__.py

synapse/rest/admin/_base.py

synapse/rest/admin/media.py

synapse/rest/admin/server_notice_servlet.py

synapse/rest/admin/users.py

synapse/util/async_helpers.py

tests/handlers/test_presence.py