Make base.html Mako template safe by default by:
1. Add page-level default of html escaping
2. Fix escaping of all variables in base.html
3. Fix escaping of all dependent underscore templates
Also includes additional best practices for certificates and
textbooks JavaScript/Underscore in order to complete that work.

TNL-3425

TNL-1653

* updating vendor files
* updating class syntax (to new FA-based classes) for all UI elements
* correcting broken tests