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.
Yes, the one in secondary nav was supposed to go, rather than "Submit a new App".  Although, we already have "Submit an App" in the top menu too, don't know if there is any reason to have them both.