Add playstream event for title_data updates

Title is fairly explanatory. I would like to be able to trigger a cloudscript event automatically when the title_data is updated. I am currently interested in title_data, not title_internal_data, although I could see similar use cases.

My immediate use case is I want to version titleData. Any updates cause the data version# to be incremented.

In the future, I would like to use this as a way to archive versions of the titleData to enable auditing/rollback.