Supported flagged revisions of W0 configurations.

* Deploy AFTER I8ef47429f38d0afe3287ec5b1a9bdd19ef4aec2d.
* An update will need to be made to mediawiki-config before this can work.
* The mediawiki-config will need to set some FR variables.
* Additionally, this WIP will need review for memcaching on FR approval.
* Additionally, this WIP will need review for roundtrip savings with a generator.
* It may turn out that the memcache and roundtrip stuff doesn't require work, but we'll see.

Change-Id: I644aecd4a6bb60cbfd371f162147d3cbf1a36ab6
Merge "Supported flagged revisions of W0 configurations."