Add log for TitleBlacklist hits

This adds a log, Special:Log/titleblacklist.
Since titleblacklist hits when editing or moving
can be triggered with GET, they are not logged.
(i.e. only local account creations are logged)

Bug: 21206
Change-Id: I1b7396cebaa528edca043d5d3dfbf9d950d0e116
Merge "Add log for TitleBlacklist hits"