Split oojs-ui from ve.ui

* Move and rename generic parts of ve.ui to OO.ui
* We now have a UI test suite because ve.Element (outside ve.ui)
  is now part of oojs-ui, so it needs a test suite.
* Added to the MW test run (just like we do for unicodejs).
* Updated csslint config (also added ve-mw and syntaxhighlight
  which were missing).

oojs-ui still depends on the TriggerRegistry in VE, this is addressed
in a follow-up commit.

Change-Id: Iec147155c1ddf20b73a4d15d87b8742207032312
Merge "Split oojs-ui from ve.ui"