ECOM-3799

We had a mechanism to, at runtime, generate a RequireJS config that
would override the base paths and, instead, use the hashed versions of
assets for things that RequireJs was loading on demand.

We've now moved that out of the coureware.html base template and into
main.html so that more pages actually benefit from it.

As well, we've added some of the heavy hitters for unhashed assets,
namely moment.min.js, to these overrides which should allow better
caching for end users.  We'll be able to add more things to the override
list in the future as they crop up.

It looks like in the past there used to be several tabs on the
course about page, but the other tabs have been commented
out years ago.

Having a single tab is pointless and confusing, so remove it.

Move tests to one test class

TNL-4160

TNL-4160

TNL-3954

- Rename escape_json_dumps to dump_js_escaped_json
- Rename escape_js_string to js_escaped_string
- Update js_escaped_string to output empty string for None
- Introduce dump_html_escaped_json
- Move dump_js_escaped_json after the pipe as new best practice
- Introduce additional uses of helpers
- Introduce new djangolib directory and move js_utils

Events are added for accessing the courseware, entering the verified
upgrade flow, and toggling a course update.

ECOM-2983

ECOM-2960

This reverts commit e8909e4439f22a7568d95a7672ab60d4a36f7322.

ECOM-2809

The existing course handouts section is moved underneath Course
Updates and News, with updated styling.

ECOM-2808

ECOM-2806

ECOM-2678

ECOM-2810

This was disabled some time ago due to PLAT-900, which caused cached
objects to be unpickled and used in new code which could expect to
find new fields that didn't exist on the old objects. That issue is
now fixed.

ECOM-2853

Updated proctored/timed exam header bar text; Upgraded edx-proctoring to pull in additional text changes

* mattdrayer: Updated get_themed_template_path

TNL-3968

-Added test for TNL-3556.

- Remove escaping in display_name_with_default
- Move escaped version to deprecated display_name_with_default_escaped
- Does not include any other changes to remove double-escaping

Thanks to agaylard who initiated this work:
https://github.com/edx/edx-platform/pull/10756

TNL-3425

Course teams occasionally upload very large files as their course
image. Before this commit, those images would be used directly in
the student's dashboard, sometimes leading to MBs worth of image
data on that page. With this commit, we now auto-generate small
and large thumbnails of configurable size. The Student Dashboard
and Course About pages will make use of this new functionality
(CourseOverview.image_urls), but the behavior of
CourseOverview.course_image_url will not change.

Note that the thumbnails are still created in the contentstore,
and sit alongside their originals.

What's included:

1. Multiple sizes, currently starting with "raw", "small", and
   "large". This falls back to the current behavior automatically in
   the case where thumbnails don't exist or this feature has been
   disabled in configuration.

2. Django admin based configuration for image sizes and whether
   to enable the functionality at all. Note that to regenerate
   images, you'd need to wipe the CourseOverviewImageSet model
   rows -- it doesn't do that automatically. This is partly because
   it's a very rare operation, and partly because I'm not entirely
   sure what the longer term invalidation strategy should be in a
   world where we might potentially have multiple themes. The
   flexible configuration was intended to allow better customization
   and theming.

3. The Course About pages also use the new thumbnail functionality,
   as an example of "large". This is in addition to the "small"
   used on the student dashboard.

Things I'm punting on for now (followup PRs welcome!):

1. Bringing the thumbnails to course discovery. A quick attempt
   to do so showed that it wasn't getting properly invalidated
   and updated when publishes happen (so the old image still showed
   up). It probably has something to do with when we do the
   re-indexing because it stores this data in elasticsearch, but
   I'm not going to chase it down right now.

2. Center-cropping. While this is a nice-to-have feature, the
   behavior in this PR is no worse than what already exists in
   master in terms of image distortion (letting the browser handle
   it).

3. Automated invalidation of the images when a new config is
   created.

TNL-2490

TNL-1957

TNL-1958