Unify the mobile menu with the desktop one.

[matteolavaggi]

The double menu creates layout variations that are now penalized by google in an important way. The "desktop" menu is outdated and really unnecessary. The layout variation could be solved by simply using only the floating menu, I can't find the code that takes care of removing the floating menu items in the desktop version. Sure it's js, any ideas? The mobile menu would be ready to use with very little variation in the template.