Add donation end-point

Make donations configurable

Added donation button to dashboard

Generalize merchant defined data for payment processor
Video module must handle xml attrs
LMS-11491
Unit test for video xml parsing
handling unknown xml attrs.
Merge pull request #5505 from edx/dhm/import_bug

Video module must handle xml attrs
Merge pull request #5502 from edx/will/per-course-donation-button

Add donation button to the enrollment success message
Removed XML information from Researchers Guide and added files to OLX

removed old comment
Merge pull request #5513 from edx/markhoeber-remove-xml-tutorial

Removed XML information from Researchers Guide
Use Backbone for student account and profile JS.

Validate student account and profile form fields. Use RequireJS for Jasmine tests of account and profile JS.