Convert some of the general database methods to async (#8100)

changelog.d/8100.misc

synapse/storage/database.py

synapse/storage/databases/main/appservice.py

synapse/storage/databases/main/events_worker.py

synapse/storage/databases/main/registration.py

synapse/storage/databases/main/roommember.py

tests/handlers/test_profile.py

tests/handlers/test_typing.py

tests/storage/test_appservice.py

tests/storage/test_base.py

tests/storage/test_event_push_actions.py

tests/storage/test_main.py

tests/storage/test_profile.py