windowManager: Add shortcut for toggling quick settings
Ever since the various status menus were combined into a single aggregate menu, the menu has been an important entry point. Alas, we never got around to adding a shortcut for it, not least because there never was a good candidate:
- "aggregate menu" never caught on as a name and super+a is taken
- "system menu" kind of works, but super+s is taken as well
- "user menu" was commonly used, but doesn't fit most of the content
That changed with the move to quick settings, which for some reason did catch on as a name outside of mockups/code. Super+q therefore became the obvious pick for a shortcut, add that.
Fixes #5670 (closed)