move My Submissions to primary nav (bug 860373)

Note that only comment #13 (https://bugzilla.mozilla.org/show_bug.cgi?id=860373#c13) is relevant. The discussion around this minor issue got a bit out of hand and was reined back in.
oh I forgot about this being removed :( this is quite useful IMO. it allows easy toggling between apps. in bram's mockups, he used the white nav bar to list the apps horizontally, which is a bit confusing IMO.