Revert non-trivial schema changes and move them to a new schema version.

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

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

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

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

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

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

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

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

synapse/storage/schema/full_schemas/16/event_signatures.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/profiles.sql

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

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

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

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

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