I want to use it e.g. for snippets and the TextEditor plugin may
not depend on the ProjectExplorer, so the code has to move.

This adds a dependency on QtQml to Utils, but that does not really
matter since that is loaded into QtCreator anyway.

Change-Id: Iada9f40b2966a1fc41631ab33da09812ad67d967
Reviewed-by: Daniel Teske <daniel.teske@theqtcompany.com>