Add tooltips for actionmenu entries

It would be nice to add tooltips on hover for the global and content menu entries, just like we have for the Watchlist entries (see watchlist.png).

The issue is that for some users the iconography might be cryptic and the tooltip might help them understand that:

• Magnifier = "Search"
• Bell = "Watchlist"
• Avatar = "User Profile"
• Hamburger = Drawer ???

• Pencil = "Edit page"
• Plus = "Create page"
• Cog = "Administer page"
• Kebab = "More actions"

Issue suggested by iinsuratelu