Merge pull request #4846 from matrix-org/hawkowl/userdir-search

changelog.d/4846.feature

synapse/app/homeserver.py

synapse/handlers/user_directory.py

synapse/server.py

synapse/storage/_base.py

synapse/storage/schema/delta/53/user_share.sql

synapse/storage/schema/delta/53/users_in_public_rooms.sql

synapse/storage/user_directory.py

tests/handlers/test_user_directory.py

tests/storage/test_user_directory.py

tests/utils.py