Please note that this is a squshed commit and the work of:
Symbolist, macdiesel, nedbat, doctoryes, muzaffaryousaf and muhammad-ammar

ECOM-2552

add new column 'copy_id_photo_from' for 'SoftwareSecurePhotoVerification' model to track initial verification with 'photo_id_key'

* Add verification deadline model.
* Populate verification deadlines from course modes table.
* Update student dashboard to use verification deadlines.
* Update pay-and-verify view to use verification deadlines.
* Simplify Django admin for course modes and add validation.
* Add verification deadline to Django admin for course modes.
* Add UI for when the upgrade deadline is missed in the pay-and-verify flow.

ECOM-1612

ECOM-1477

Added a banner that students can use to dismiss the "you have failed reverification" message.  Also, removed unused code, wired up the sidebar for design

Added verification sidebar, banner for major courseware sections, quality & test improvements

Improved tests, fixed javascript for photocapture, removed extraneous photocapture code, added time & course numbers to templates for design

Quick-and-dirty end-to-end flow, functional for at least the case of one course in need of re-verification.

Ready for design to start taking a look; still needs tests and code cleanup