Basic architecture of Maintenance App - SUST-19, SUST-42. Implement Force Publish Course view. SUST-46

Revert "Basic architecture of Maintenance App - SUST-19, SUST-42. Implement Force Publish Course view. SUST-46"

This reverts commit 27646b7e.

The LMS continues to expect lowercased category slugs, while the Studio program creator now uses correctly cased slugs. Programs should be updated before this is released. Part of ECOM-5018.

Basic architecture of Maintenance App - SUST-19, SUST-42. Implement Force Publish Course view. SUST-46

TNL-4670

TNL-4906 Subsections now use radio buttons, to allow for "hide after due" as a
visibility option. Also, all tabs have been consolidated to "Basic" and
"Advanced", and visibility options have moved there.

Documentation links are updated to assist course authors with the new
visibility options. Tests have also been updated, and the changes suggested
in TNL-4951 are included.

TNL-4805

TNL-4799

TNL-4692

show Save and Cancel button when admin change Instructor image asset path from Studio schedule and details page

TNL-4366
Changes in studio to allow the hide_after_due setting to be utilized.

Includes:
    -python changes to contentstore, where the data is stored.
    -refactoring of timed-examination-preference-editor.underscore, to add this
        setting and make the editor more accessible.
    -javascript changes to link the new setting to the correct data model.
    -sass updates to fix a11y issues on the editor modal.
    -addition of post-due visibility information to course outline in studio.
    -new tests: python, js, acceptance, and a11y

TNL-4366
Changes in studio to allow the hide_after_due setting to be utilized.

Includes:
    -python changes to contentstore, where the data is stored.
    -refactoring of timed-examination-preference-editor.underscore, to add this
        setting and make the editor more accessible.
    -javascript changes to link the new setting to the correct data model.
    -sass updates to fix a11y issues on the editor modal.
    -addition of post-due visibility information to course outline in studio.
    -new tests: python, js, acceptance, and a11y

Use new best practices.

FEDX-24

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