[SCHEMA CHANGE] Refactor of moderation logging.

* Store moderation reason in object.
* Use a LifecycleHandler to do logging rather than doing it directly.
* Includes permalink handling for the logging class. Unfortunately not backwards compatible.

Bug: 57055
Bug: 57056
Change-Id: Idd5a6570268e480c9cbe2c9620dfbb587db71ee4