Fixes #608 make exclusive more configurable on wayland

[viandoxdev]

Description

Changes the exclusive property on wayland to allow for another option: ignore

Usage

  :exclusive "exclusive" ; reserve space
  :exclusive "normal" ; default behavior
  :exclusive "ignore" ; don't move window if occluding another

Additional Notes

Not a fan of the names exclusive, normal, ignore, :exclusive "exclusive" looks weird and they're not really explicit.
Pretty sure this count as a breaking change too.

Checklist

• All widgets I've added are correctly documented.
• I added my changes to CHANGELOG.md, if appropriate.
• The documentation in the docs/content/main directory has been adjusted to reflect my changes.
• I used cargo fmt to automatically format all code before committing

[elkowar]

Yea, having the breaking change here is kind of annoying... I'd love to either include this in a release that already includes other breaking changes, or make it not break the current format. Any ideas as to how you could implement this without breaking backwards-compatibility?

[w-lfchen]

i propose still supporting exclusive and adding a new option instead, maybe something like reserve, in which the user may directly define the amount of space to reserve, that number is then passed to gtk_layer_shell::set_exclusive_zone directly, overriding exclusive, if both are set (this needs to be documented, of course).
the exclusive docs could be updated to mention that this simply automatically reserves space.

this would allow the use case of someone wanting to partially overlap their bar over windows if i understand the protocol right.
don't know whether someone would do that, but providing more options hardly seems like a bad idea.

i offer adopting this pr and trying to get this feature implemented at some point if that's wanted.