Move QmlConsole to Debugger

Now it is closer to its only user and possibly reusable for no-QML uses
there.  We also drop the QML/JS syntax checker. The application being
debugged can already tell us about syntax errors. There is no need to
duplicate that functionality.

Change-Id: I2ba151f9f4c854c6119ba5462c21be40bddcebf9
Reviewed-by: Ulf Hermann <ulf.hermann@theqtcompany.com>
Reviewed-by: hjk <hjk@theqtcompany.com>