Merge branch 'release-v0.25.0' of github.com:matrix-org/synapse

CHANGES.rst

README.rst

docs/code_style.rst

docs/password_auth_providers.rst

docs/url_previews.md

docs/user_directory.md

scripts/synapse_port_db

synapse/__init__.py

synapse/app/frontend_proxy.py

synapse/app/homeserver.py

synapse/appservice/api.py

synapse/config/cas.py

synapse/config/logger.py

synapse/config/password_auth_providers.py

synapse/config/server.py

synapse/config/tls.py

synapse/federation/federation_server.py

synapse/federation/transport/client.py

synapse/federation/transport/server.py

synapse/groups/attestations.py