Everywhere: It's now "Foobar", not "FooBar", and not "foo bar"

I hereby declare these to be full nouns that we don't split,
neither by space, nor by underscore:

- Breadcrumbbar
- Coolbar
- Menubar
- Progressbar
- Scrollbar
- Statusbar
- Taskbar
- Toolbar

This patch makes everything consistent by replacing every other variant
of these with the proper one. :^)

Userland/Services/WindowServer/MenuManager.h

@@ -27,7 +27,7 @@
 #pragma once
 
 #include "Menu.h"
-#include "MenuBar.h"
+#include "Menubar.h"
 #include "Window.h"
 #include <AK/HashMap.h>
 #include <AK/StringBuilder.h>