[PD-878] Made sure that page indication happens on sub pages as well.

I also removed navigation from the forms in the myjobs templates. It's already the case in microsites.
It's probably time to consolidate this logic. We're setting and checking on_page values in the postajob views, postajob_navigation, and now these 17 templates. I realize this is how we do it on mypartners, but this is getting too complicated to add new pages in the future. Would a template tag that looks at the request path have enough information to replace the on_page from the view?