Improve window state handling

[Ottatop]

This PR comes with improvements to window state handling (floating, fullscreen, maximized).

Improvements include:

• Pinnacle will now finally attempt to open Wayland windows as floating when necessary, like the save prompt in Firefox. This closes Detect Wayland windows that should be floating #85 which was opened a whopping 9 months ago haha
• Fixed the bit where you could drag fullscreen and maximized windows when the window was previously floating
• Fixed xterm taking like 5 seconds to open
  • In classic xwayland fashion, this introduces a regression where you now need to run Intellij Idea with _JAVA_AWT_WM_NONREPARENTING=1 to get it to appear correctly

Things that need doing and thinking about:

• I really don't like what WindowElementState::floating_or_tiled is doing. It's currently pulling double duty as the holder for the current floating/tiled state of the window and it gets used as a marker for what state gets applied when exiting fullscreen or tiled mode; both "prescription" and "description". Find a way to separate its duties.
  • Unified floating_or_tiled with the fullscreen_or_maximized state, which now feeds into Pinnacle::update_window_state.
• As a result of the above, the API should be updated to unify those states into something like enum { Tiled, Floating, Fullscreen, Maximized }