Updating the footer for edx.org and open edx.

Making the footer look more like the front page.

* Updated SASS for footer
* Updated HTML for open edx and edx.org templates
* Updated stubbed views
* Added !important SASS to overwrite some blanket LMS styles

Updating steve.m.sandbox.edx.org to have the latest changes.
@wedaly @andywaldrop @dianakhuang @griffresch 

In another PR that had temporary feature flags, we added a "TODO (TICKETNUM-00): Remove this when we're done with whatever" comment everywhere the feature flag was referenced.  Would it be a good idea to do that here, so we don't have "use the new footer" lying around everywhere forever?