X.H.StickyWindows: Stick windows on screens

[TheMC47]

Description

After checking #797 and xmonad/xmonad#445, I was motivated again to pick this up again.

This is a draft for actually sticky windows, not like X.A.CopyWindow: make a window stick on a screen and move whenever the workspace changes. This requires xmonad/xmonad#433 to work, without it I was struggling to debug why xmonad hangs.

I still need to adapt the docs and actually test this on two screens.

Checklist

• I've read CONTRIBUTING.md

• I've considered how to best test these changes (property, unit,
  manually, ...) and concluded: I don't have access to a second screen for the next week or two,
  so I'll still have to test this

• I updated the CHANGES.md file

• Finish Write docs

[slotThe]

@TheMC47 any updates on this?

[TheMC47]

@slotThe it's been working flawlessly for me. It depends on xmonad/xmonad#433 to work though. Once we can get that merged, I can find the time to finish the docs and maybe add some "quality of life" changes (like a setting to automatically float sticky windows or add some manage hook utilities).

Should've pushed more on xmonad/xmonad#433, but life got busy lately