remove CertificateStatuses.regenerating

Updated dashboard UI for empty list of courses and programs

-Adressed all comments

Updated dashboard UI for empty list of courses and programs

Resolves conflicts between reverts of pattern library test pages and multi-site comprehensive theming, and the re-introduction of pattern library test pages. Fixes a pipeline rendering test which relied on other tests updating assets. The test now ensures that static assets are available before running.

This reverts commit 628843f6.

-Updated method "course_key_from_string_or_404" to raise message too.
-Wrote tests for "course_key_from_string_or_404" when exception message is given.
-Modified existing methods to use "ddt.data".
-Used Splunk logs to find exectly where we were getting "Invalid Key Error"
-Updated Views where we were getting "Invalid Key Error" in splunk logs.
-Wrote tests for those View End points where we were getting "Invalid Key Error"

Updated dashboard UI for empty list of courses and programs

The verification workflow assumes that all verified courses will have a
price. Free verified course modes cause a 404 when the user attempts to
enroll or upgrade.

This reverts commit 09586d8a.

This reverts commit a796b563.

Conflicts:
	lms/envs/common.py
	openedx/core/djangoapps/theming/models.py
	pavelib/assets.py
	pavelib/paver_tests/test_assets.py

The old code set the output-encoding to None, which means, I want
Unicode strings as output.  This made Mako pass markupsafe objects to
"unicode()", which applied all the escaping.  Then the result would be
given to Django, would would html-escape it again, resulting in
over-escaping.

By setting the output-encoding to utf8, we use filters.encode.utf8
instead, which is aware of Markupsafe, which avoids the over-escaping.

FEDX-93

These are developer only pages, so can not be seen in production
environment. On devstack, you can access these pages in LMS and
Studio at:

    /template/ux/reference/pattern-library-test.html

This is the second attempt to enable the Pattern Library. The
first attempt broke Django Templates and didn't work correctly
with right-to-left styling.

This reverts commit 845e3708.

This reverts commit 845e3708.

TNL-4296

- Icon images can be uploaded from the django admin
- Test coverage improved

This includes the course key/path for a given contentserver request,
whether or not the asset is locked, cacheable, has been modified, etc.

This should give us some better insight as to what sort of requests are
coming into the contentserver to figure out whether or use of a CDN in
front of these assets is as efficient as effective as it could be.

FEDX-93

These are developer only pages, so can not be seen in production
environment. On devstack, you can access these pages in LMS and
Studio at:

    /template/ux/reference/pattern-library-test.html

The listed languages in the "preferred languages" input dropdown should
be translated in the user language.

- Icon images can be uploaded from the django admin
- Test coverage improved

Available backends:

* django-oauth-toolkit (DOT)
* django-oauth2-provider (DOP)

* Use provided client ID to select backend for
  * AccessToken requests
  * third party auth-token exchange
* Create adapters to isolate library-dependent functionality
* Handle django-oauth-toolkit tokens in edX DRF authenticator class

MA-1998
MA-2000

MA-1998 Install and configure django_oauth_toolkit to coexist with
existing oauth libraries.