Menu of components (#131)

Allow Container::Vertical and Container::Horizontal to have an
external selector, similar to Container::Tab.

This is useful for implementing a menu of menu.

Co-authored-by: ArthurSonzogni <sonzogniarthur@gmail.com>

examples/component/CMakeLists.txt

@@ -12,6 +12,7 @@ example(homescreen)
 example(input)
 example(menu)
 example(menu2)
+example(menu_multiple)
 example(menu_style)
 example(modal_dialog)
 example(radiobox)