Push bulk indexing onto the job queue

Add an extra parameter to forceSearchIndex.php which, when set, will
cause updates to be pushed onto the job queue and processed there.

Because it came up in code review, this renames
CirrusSearchUpdater::updateRevisions to updatePages which is more
correct - it doesn't deal in pages.  That causes a small raft of
renames.

During the rename I alsmo removed some revision related stuff in
forceSearchIndex.php which wasn't required.

Change-Id: Id17b807f9b209a7da9caf7e314e41f6dc3ff5879
Merge "Push bulk indexing onto the job queue"