ECOM-2866

This is a squash of 38 commits ending with
5b080f979d692804452400ac5bed9b17c50b001e

ECOM-2172

- Updated checkout page to disallow purchase of credit seats (the credit payment page is hosted in ecommerce)
- Corrected path to providers endpoint
- Cleaned receipt page styling
- Updated receipt page copy
- Added provider thumbnail to receipt page

ECOM-2172

ECOM-1808

* Delete reverification templates
* Delete photocapture.js
* Delete unused "name change" end-points
* Rebuild the reverification views using Backbone sub-views
* Stop passing template names to the JavaScript code
* Avoid hard-coding the parent view ID in the webcam view (for getting the capture click sound URL)

The payment buttons now match the style of the verified upgrade buttons.

XCOM-422

As part of the unification of verify later/now, the take photo page needs to list the verification requirements.

XCOM-254

ECOM-1470

* simplifying edx.org breakpoints to use min-width
* creating -bp-* centric Sass variables
* converting all existing edx.org centric media queries to use new Sass variables

ECOM-1457

(SOL-531)(SOL-532)Course Cards update; A link to course discovery page has been added to the OpenEdX homepage

ECOM-1228

Add support for HTML Media Capture (file input)
so that iOS users can use the camera.

SASS compilation variable conventions update, focusing on basic colors, baseline variable usage for padding and margins, ui-depth extends, along with other small fixes. The intent with this is to not have any user-facing impact, and instead move us closer toward having files that use our newer sass conventions.

UX-351