[Completes #44026271] Private beta users can learn about and install the discovery bar
[Completes #43968879] Developer can navigate to create a new app
Change association between App and OauthScope to has_many, through instead of has_and_belongs_to_many.
[Completes #43875895] Developer can add scopes when creating an app.
Only show apps/new errors block if there are any errors.
Update JSON gem to 1.7.7