Add stretching of modules and modules-center toggling

This Patch allows the stretching of modules-{left,center,right} as well
add a "expand" flag to AModule. This allows one module to consume the
leftover space.
To allow the left or right modules to fully consume the center, the
changes also include a way to remove the center box (center_)
altogether.

man/waybar-hyprland-workspaces.5.scd

@@ -78,6 +78,11 @@ Addressed by *hyprland/workspaces*
 	If set to id, workspaces will sort by id.
 	If none of those, workspaces will sort with default behavior.
 
+*expand*: ++
+	typeof: bool ++
+	default: false ++
+	Enables this module to consume all left over space dynamically.
+
 # FORMAT REPLACEMENTS
 
 *{id}*: id of workspace assigned by compositor