feat: allow moving focus to floating windows with keyboard shortcuts

[Daxtorim]

Summary

Before, switching focus with keyboard shortcuts was only possible between tiled windows. Now one can also navigate to floating windows.

When finding candidates for focus switching, floating windows will be treated as smaller than they really are. This means that floating windows can overlap tiled windows slightly without automatically becoming the first choice for focus switching. This improves navigation around floating windows as switching behavior will feel more predictable.

Test Plan

1. Install PR version of script
2. Open a few windows
3. Make one window floating
4. Try to navigate to that window with only keyboard shortcuts

https://user-images.githubusercontent.com/72616153/143285123-1fec66c8-4220-409f-8870-7965ec428522.mp4

[gikari]

This needs to be rebased.

[Daxtorim]

Ready for review.