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/DevTools/HackStudio/main.cpp

@@ -34,7 +34,7 @@
 #include <LibCore/EventLoop.h>
 #include <LibCore/File.h>
 #include <LibGUI/Application.h>
-#include <LibGUI/MenuBar.h>
+#include <LibGUI/Menubar.h>
 #include <LibGUI/MessageBox.h>
 #include <LibGUI/Notification.h>
 #include <LibGUI/Widget.h>
@@ -97,7 +97,7 @@ int main(int argc, char** argv)
 
     s_window->set_title(String::formatted("{} - Hack Studio", s_hack_studio_widget->project().name()));
 
-    auto menubar = GUI::MenuBar::construct();
+    auto menubar = GUI::Menubar::construct();
     s_hack_studio_widget->initialize_menubar(menubar);
     s_window->set_menubar(menubar);