SOL-258 Removing preview and content type from search list for sequence ...

Combine the changes of SOL-199 and SOL-221

Multi-commit history:
- hide drag functionality for entrance exam section.
- hide entrance exam subsection elements e.g. delete, drag, name etc.
- show unit/verticals expanded in case of entrance exam
- modify code in order to allow user to update entrance exam score from UI.
- write down unit tests.
- write down Jasmine tests.
- add bok-choy test
- updated bok-choy test
- internationalize string
- repositioned sequential block creatori
- SOL-221 (entrance exam message)
- SOL-199 LMS Part (show entrance exam content) and hide the course navigation bar.
- redirect the view in case of entrance exam.
- update code structure as per suggestions
- write down unit tests
- fix pep8
- instead of hiding the exam requirement message, now also showing the exam the completion message (success state).
- write down unit test to show exam completion message.
- Update code as per review suggestions
- update doc string
- addressed review suggestions
- change sequential message text
- css adjustments
- added new css class for entrance exam score in studio
- added Jasmine test for remaning coverage
- sequential message should appear under the context of entrance exam subsection.
- updated text in CMS and LMS as per suggestions.
- added unit text to insure sequential message should not be present in other chapters rather then entrance exam.
- skip setter if empty prerequisite course list
- exclude logic from xblock_info.js that is specifically related to entrance exam.
- added js tests and updated code as per suggestions
- added tests
- addressed several PR issues
- Several small fixes (style, refactoring)
- Fixed score update issue
- added some more unit tests.
- code suggested changes.
- addressed PR feedback

return proper 404 for assets of some invalid course from split modulesto...

PLAT-456

Upgrade PDF.js library from v0.8.1243 -> v1.0.907

china video cdn experiment

ECOM-1140: Instructor dashboard example certificates

Match Studio logo logic to LMS

Add flaky decorator.

Allow global staff to generate example certificates
on the instructor dashboard.

Allow global staff to enable/disable self-generated
certificates for a course.

Change .md file to .rst.

Related to TNL-1642.

Related to TNL-1619.

Fix failing forums unit test.

Ned/finish pr 7232

Certificate status when XQueue is unavailable.

Add empty introspection rule for BlockTypeKeyField.

Use 'edx_lint write' to create our pylintrc from pylintrc_tweaks

Revert "Merge pull request #6771 from edx/dan-f/forums-filter-discussion...

Awais786/ecom 1158 upgrade page

Show a select box when editing a library content block (SOL-123)

use 'commit_on_success' transaction decorator to avoid registering users...

From 0.7 on, South requires explicit introspection rules. Previously, it used the parser module to introspect.

This reverts commit 086a2ba7, reversing
changes made to a44132ec.  Some minor
code quality issues were addressed as part of this change.

Conflicts:
	lms/djangoapps/django_comment_client/base/views.py
	lms/djangoapps/django_comment_client/utils.py