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/BrowserWindow.gml

@@ -1,7 +1,6 @@
 @GUI::Widget {
     name: "browser"
     fill_with_background_color: true
-
     layout: @GUI::VerticalBoxLayout
 
     @GUI::HorizontalSeparator {

Userland/Applications/Browser/EditBookmark.gml

@@ -2,17 +2,13 @@
     fixed_width: 260
     fixed_height: 85
     fill_with_background_color: true
-
     layout: @GUI::VerticalBoxLayout {
         margins: [4]
     }
 
-
     @GUI::Widget {
         fixed_height: 24
-
-        layout: @GUI::HorizontalBoxLayout {
-        }
+        layout: @GUI::HorizontalBoxLayout
 
         @GUI::Label {
             text: "Title:"
@@ -27,9 +23,7 @@
 
     @GUI::Widget {
         fixed_height: 24
-
-        layout: @GUI::HorizontalBoxLayout {
-        }
+        layout: @GUI::HorizontalBoxLayout
 
         @GUI::Label {
             text: "URL:"
@@ -42,15 +36,11 @@
         }
     }
 
-
     @GUI::Widget {
         fixed_height: 24
+        layout: @GUI::HorizontalBoxLayout
 
-        layout: @GUI::HorizontalBoxLayout {
-        }
-
-        @GUI::Widget {
-        }
+        @GUI::Widget
 
         @GUI::Button {
             name: "ok_button"

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 {