hyprland/workspaces: allow using the original window class/title

[scgtrp]

This turns the values of window rewrite rules in hyprland/workspaces from static strings to format strings with the values {class} and {title} available.

For example, I'm now doing this to list windows in each workspace without having to add a rule for every application I use:

  "hyprland/workspaces": {
    "format": "{name}: {windows}",
    "window-rewrite-default": "{class}",
  },

[Alexays]

Thanks!