GitLab

This is basically a continuation of the commits which
refactor code out of the base text editor. For instance,
36fa1de4 and
3a684586.

Also removed the doXXXX() forwarding methods.

Reviewed-by: Thorbjorn Lindeijer

The QML task manager behaviour is to show warnings/errors for _saved_ files
only.

Fix namespace usage such that all classes in shared/qml live in the
Qml namespace, and classes in QmlDesigner plugin in the QmlDesigner
namespace.

This should prevent any symbol clashes until we can finally get rid
of the file dublicates (e.g. QmlDocument).

Reviewed-by: Erik Verbruggen