Use unsigned bigint

synapse/storage/schema/delta/12/v12.sql

synapse/storage/schema/delta/13/v13.sql

synapse/storage/schema/delta/16/users.sql

synapse/storage/schema/full_schemas/11/event_edges.sql

synapse/storage/schema/full_schemas/11/im.sql

synapse/storage/schema/full_schemas/11/keys.sql

synapse/storage/schema/full_schemas/11/media_repository.sql

synapse/storage/schema/full_schemas/11/presence.sql

synapse/storage/schema/full_schemas/11/transactions.sql

synapse/storage/schema/full_schemas/11/users.sql

...e/storage/schema/full_schemas/16/application_services.sql

synapse/storage/schema/full_schemas/16/event_edges.sql

synapse/storage/schema/full_schemas/16/im.sql

synapse/storage/schema/full_schemas/16/keys.sql

synapse/storage/schema/full_schemas/16/media_repository.sql

synapse/storage/schema/full_schemas/16/presence.sql

synapse/storage/schema/full_schemas/16/push.sql

synapse/storage/schema/full_schemas/16/transactions.sql

synapse/storage/schema/full_schemas/16/users.sql