Avoid header notice log spam from RunJobs API

* Moved ApiRunJobs to a special page instead of going through
  ApiMain and having to fight the logic there. As a separate
  internal API, this does not show up on the API help page and
  is no longer effected by $wgEnableAPI.

bug: 62233
Change-Id: I1db6f526d02e130a66ee03289858a734d89e6c00