Admin Overlay stacking and ghost hiding (#35622)

Admin Overlay stacking and ghost hiding (#35622)

* ghostbuster mouse and overlay stacks

* variable adjustment

* use map coords for distance check

* vertical stack ordering, and cvars

* skreee

* fix stack merge 'sidedness' issue

* overlays no longer try to stack to overlays at the wrong coordinates

* options slider for stack merge distance

* admin option sliders for ghost fade/hide

* Update AdminOptionsTab.xaml.cs

---------

Co-authored-by: ScarKy0 <scarky0@onet.eu>