Generate recentchanges rows from Flow

Inserts changes to the core recentchanges table and attaches
to proper events to receive and format them for viewing.  Allows
editors to continue using watchlists with flow. After merging the
code to allow individual pages to be taken over by flow this will
need tweaks to link appropriatly to either Special:Flow or the
taken over title.

Includes a refactor of how we handle revision comments.  Essentially
this field is an i18n key that represents the type of action which
created the revision.  All of these should now be prefixed
flow-rev-message-*

Change-Id: Ie1fa4ed5511ba04c07bf16f1bbc1263b904cb8fc
Merge "Generate recentchanges rows from Flow"