Removed the deprecated app_name usage from lms/urls.py BOM-1155

Add way to get YouTube metadata that doesn't require a session cookie

BOM-1145 : Django 2.2 Supported version of sorl-thumbnail

Unsubscribe link added in bulk emails

BOM-1141 Upgrade social-auth-app-django

The Video Player XBlock will sometimes make API calls to /couses/yt_video_metadata, a REST API endpoint that in turn loads video metadata from YouTube using the configured settings.YOUTUBE_API_KEY.

However, in the Blockstore-based XBlock runtime, we are running XBlocks in a secure sandbox, and the user's browser cannot pass session cookies when calling REST API endpoints. So currently, the video XBlock tries to request YouTube metadata from that API endpoint, but it fails if run within such a sandbox.

The existing API also doesn't work for anonymous users (users who are allowed to see video XBlocks but who have not logged in to an LMS user account).

This commit updates the Video XBlock so that it can use a handler to load the data from YouTube instead of a generic REST API. This works well in the new runtime, because it has code to support calling handlers within the sandbox, including by anonymous users.

I also fixed a bug where on a default devstack, the endpoint will try calling YouTube using PUT_YOUR_API_KEY_HERE as an API key, and get a "bad request" error from YouTube.

The code could be re-organized by moving things around, but I've left everything as-is for now to keep the diff as small as possible.

Dont delete course overviews

Merge pull request #22876 from edx/testeng/bokchoy_auto_cache_update_e00340173c2d18e4052a08fe465230530b2d3202

Bokchoy Testing DB Cache update

Update edx-val from 1.2.0 to 1.2.1

Added the link to latest master commit of GitHub for Django 2.2 support.

Fix footer link for wcag.

BOM-1126

Awais786/bom 1050

Removing the moto.

remove the logs

django-appconf bump version using commit hash for django2.2

BOM-1126

PROD-604

This is step 3 of DE-1824.

Also update:
* six 1.13.0 => 1.14.0
* edx-django-utils 2.0.2 => 2.0.3
* skip test that checks all model changes have migrations.  (We defer
  this to step 4.)

Fix: KeyError: 'source' when parsing HTML5 videos

Add TeamsConfigurationService to lms xblock runtime

Rather than deleting CourseOverviews to update their version numbers, just reload them from the modulestore

This fixes a bug that causes the video XBlock parsing to break in the new XBlock runtime if:
* the html5_sources field is set, and
* the download_video field is not set

The error is:

  File "/edx/app/edxapp/edx-platform/openedx/core/djangoapps/xblock/rest_api/views.py", line 52, in render_block_view
    block = load_block(usage_key, request.user)
  File "/edx/app/edxapp/edx-platform/openedx/core/djangoapps/xblock/api.py", line 84, in load_block
    return runtime.get_block(usage_key)
  File "/edx/app/edxapp/edx-platform/openedx/core/djangoapps/xblock/runtime/blockstore_runtime.py", line 70, in get_block
    block = block_class.parse_xml_new_runtime(xml_node, runtime=self, keys=keys)
  File "/edx/app/edxapp/edx-platform/common/lib/xmodule/xmodule/video_module/video_module.py", line 620, in parse_xml_new_runtime
    setattr(video_block, key, cls.fields[key].from_json(val))
  KeyError: 'source'

The reason for the error is that parse_video_xml() will sometimes return a 'source' attribute in its field_data return value, even though source is not a video field (anymore). This then causes an error when trying to look up cls.fields['source']

A workaround in the meantime is to add download_video="false" to the OLX.

Removing the moto from repo.

Python Requirements Update

Implementation of metadata endpoint for sequence modules