Meta+Userland: Run the GML formatter on CI and pre-commit

Now that the GML formatter is both perserving comments and also mostly
agrees to the existing GML style, it can be used to auto-format all the
GML files in the system. This commit does not only contain the scripts
for running the formatting on CI and the pre-commit hook, but also
initially formats all the existing GML files so that the hook is
successfull.

Userland/Applications/Browser/Tab.gml

@@ -5,7 +5,6 @@
 
     @GUI::ToolbarContainer {
         name: "toolbar_container"
-
         @GUI::Toolbar {
             name: "toolbar"
         }
@@ -13,8 +12,8 @@
 
     @GUI::Widget {
         name: "webview_container"
-        layout: @GUI::VerticalBoxLayout {
-        }
+        layout: @GUI::VerticalBoxLayout
+
     }
 
     @GUI::Statusbar {