Add NSStatusItemSpacing and NSStatusItemSelectionPadding

Add `NSStatusItemSpacing` and `NSStatusItemSelectionPadding` to `NSGlobalDomain` options.

These options control the spacing between and padding inside status icons in the menu bar. With these options, it's possible to squeeze more items on the menu bar, something that's especially useful on machines with a notch.

This is a copy of LnL7#872, which was closed without being merged.

modules/system/defaults/NSGlobalDomain.nix

@@ -248,6 +248,24 @@ in {
       '';
     };
 
+    system.defaults.NSGlobalDomain.NSStatusItemSpacing = mkOption {
+      type = types.nullOr types.int;
+      default = null;
+      example = 12;
+      description = ''
+        Sets the spacing between status icons in the menu bar. The default is null.
+      '';
+    };
+
+    system.defaults.NSGlobalDomain.NSStatusItemSelectionPadding = mkOption {
+      type = types.nullOr types.int;
+      default = null;
+      example = 6;
+      description = ''
+        Sets the padding around status icons in the menu bar. The default is null.
+      '';
+    };
+
     system.defaults.NSGlobalDomain.InitialKeyRepeat = mkOption {
       type = types.nullOr types.int;
       default = null;