Cancel the processing of key query requests when they time out. (#13680)

changelog.d/13680.feature

synapse/api/auth.py

synapse/handlers/device.py

synapse/handlers/e2e_keys.py

synapse/rest/client/keys.py

synapse/storage/controllers/state.py

synapse/storage/databases/main/devices.py

synapse/storage/databases/main/end_to_end_keys.py

synapse/storage/databases/main/event_federation.py

synapse/storage/databases/main/events_worker.py

synapse/storage/databases/main/roommember.py

synapse/storage/databases/main/state.py

synapse/storage/databases/main/stream.py

synapse/storage/databases/state/store.py

synapse/storage/util/partial_state_events_tracker.py

synapse/types.py

tests/http/server/_base.py

tests/rest/client/test_keys.py