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/Menu.h

@@ -41,7 +41,7 @@
 namespace WindowServer {
 
 class ClientConnection;
-class MenuBar;
+class Menubar;
 
 class Menu final : public Core::Object {
     C_OBJECT(Menu);