Convert misc database code to async (#8087)

changelog.d/8087.misc

synapse/storage/background_updates.py

synapse/storage/databases/main/devices.py

synapse/storage/databases/main/event_push_actions.py

synapse/storage/databases/main/presence.py

synapse/storage/databases/main/push_rule.py

synapse/storage/databases/main/pusher.py

synapse/storage/databases/main/receipts.py

synapse/storage/databases/main/roommember.py

synapse/storage/databases/main/state.py

synapse/storage/databases/main/user_erasure_store.py