This commit:
1. removed the possibility to create page from the menu manager.
The usability of this feature wasn't great since create menu as a new page
would redirect to that newly created page without saving the menu manager
state.
Plus, there is already the 'NEW' button on the navbar to create a new page,
the menu manager should, as its name hint, only manage menus.
2. Handle a new case (officially at least) of menu: menu container.
Those menu are simply menus with '#' as URL. It will be usefull to create a
menu as a dropdown list container.
Note: We should take care of a menu's URL being updated to '#' to avoid the
menu's page URL to be also edited to '#'.
opw-1825883 & opw-1824263
Romain Derie
b65cb86697