Reduce clutter on global edit mode toolbar

The global edit mode toolbar has a lot of stuff on it, some of which is not very relevant to editing the desktop and panels or isn't important to have here:

1. "Global Themes" doesn't have anything to do with the desktop and panels.
2. "Display Configuration" doesn't have anything to to with the desktop and panels, and is also visible in the menu used to enter edit mode in the first place.
3. "Wallpaper and desktop" definitely does have something to do with the desktop and panels, but it's not only visible in the menu used to enter edit mode in the first place, and also the wallpaper component is also visible in System Settings now, making access from here less unnecessary.

If you manage to enter edit mode using a touchscreen, the full contents of the desktop context menu are available via a hamburger button on the global edit mode toolbar as well.

As such, these items are mostly clutter on the toolbar, so let's remove them to clean up the presentation of what matters most.

Requires plasma-workspace!5027 (merged) to change the button text on the toolbar.

Before	After

@teams/vdg @teams/usability