Unlink maximization state from actual geometry

Since clients with restricted geometry now cannot cover the entire screen by default it was necessary to unlink the state from the actual geometry to re-provide the "restore" feature.
The patch also extends the protection of the maximized state to unilateral maximizations (emacs issue)

BUG: 265568
BUG: 252314
CCBUG: 252255
review request https://git.reviewboard.kde.org/r/100606/