hyprland/ipc: expose HyprlandToplevels, as exposed by Hyprland's IPC

[Maeeen]

This PR:

• adds more exposed properties from Hyprland's IPC for toplevelsin HyprlandToplevel, e.g., whether the toplevel is urgent (not everything is present though)
• bidrectional handles between an HyprlandToplevel and a Toplevel (Wayland)
• adds a list of toplevels per workspaces, including whether they have an urgent toplevel or not

… and some testers.

[outfoxxed]

Looks pretty good. In general avoid code directly after a }, and make sure you run the formatter.

[Maeeen]

I have applied the appropriate fixes (I believe.) Should be good now. Normally, just fmt and just lint-changed are okay with my changes

[outfoxxed]

I've got a couple minor formatting nitpicks but it will be easier for me to just fix them when I merge it. Thanks!