Enable Video Uploads by default with course rollout flag.

* Vertical marks blocks completed when viewed.
* Functionality is hidden behind a waffle switch
* Submissions from front-end are limited to known-incomplete blocks
* Upgrades xblock to version 1.1.1
* Related future requirements listed in TODO tagged with EDUCATOR-1778
  and relevant opencraft OC-* ticket IDs.

OC-3088

This is running decaffeinate, with no additional cleanup.

Step 1 in our migration steps is to rename the CoffeeScript files to
the JS files they will be replaced with, so that we can preserve file
history.

New management command for setting up a test environment. The command creates a ScheduleConfig and schedules if they don't exist (the schedule starts three days before the time the command is run). If a schedule already exists, the command updates the schedule's start time and upgrade deadline. The values set by the command will allow send_recurring_nudge to send three-day nudges.

Doing it at the modulestore level does not cover all usages of mongo,
for example when connecting to the contentstore.

EDUCATOR-1555

Anonymous users may now view units in the courseware. This access is limited to units that are not considered problems/graded (e.g. homework, exams).

EDUCATOR-1409

LEARNER-2754

to allow the HTML to be downloadable via the Course Blocks API.

Feature flag ENABLE_HTML_XBLOCK_STUDENT_VIEW_DATA must be set to enable this feature.

LEARNER-2977

Fixes

In docs it is explained that we should show "Show Answer" button for "Answered" value when the user has correctly submitted the answer. The current behavior is such, even if the learner has answered the question wrong, the "Show Answer" button would be available.

EDUCATOR-1563

LEARNER-1923

Adds val trancripts in outcome of get_transcripts_info and rest of flow remains the same and also add fallback  to edx-val rtanscripts for mobile accessible video endpoints.

Purpose of this, is to serve transcripts from edx-val if the requested transcripts are not found in the contentstore i.e. that's where all the transcripts are living to date.

EDUCATOR-1216