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 

My opinion is the broken links are totally fine, we already do this elsewhere eg https://github.com/edx/edx-platform/blob/master/lms/templates/courseware/course_about.html#L255