Refactor remaining Vex actions/buttons/etc. to the command framework [was #8254]
Due to the Vex legacy, we currently have a mix of old proprietary Vex stuff (intended for Swing compatibility) with their adaptions to the old Eclipse action framework, own actions created in the VexEditor constructor, and Command framework stuff.
We should refactor this to the modern Command framework for consistent handling, especially since some bugs (like TG-828) appear to be much easier to resolve with the command framework instead of proprietary hacks for the old stuff.