Display warning message on course outline in Studio when course contains deprecated features/components

TNL-2303

Clicking on conflicting option box unchecks all conflicts
LMS: Clicking license text should bring to new window
updated styles to reflect html reuse inside of xblock edit modal area.

Add ARIA attributes to license for a11y

Gracefully handle re-selecting of selected license

Use native checkboxes for courseware license options
In Studio settings editor for video module, don't show license if feature-flagged off
Don't let Scope.contents fields leak to Studio editor
JS gettext() must all be on the same line for i18n
Add docstrings for bok-choy tests
Remove LicenseMixin from HTMLDescriptor
Responding to UX review feedback
Add aria-pressed attribute
Use https links instead of protocol-relative links for links to creativecommons.org
Remove license from course outline page in Studio

This allows course authors to choose between two difference licenses for their
course content: All Rights Reserved, or Creative Commons. In the backend, XBlocks
that wish to allow custom licenses need only inherit from LicenseMixin, which
adds a `license` field as a string.

License information is displayed in the Studio editor view, and just below the
rendered XBlock in the LMS. In addition, if the course block itself has a custom
license set, this license will display just below the main body of the page
on courseware pages.

This entire feature is gated behind the LICENSING feature flag.

The "New Course" and "New Library" buttons reveal a form to add course or library.
When not displayed, these forms are still accessible to a keyboard user.
Added display: "none" in css so that contents are visually as well as via
keyboard inaccessible

AC-34

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

TNL-652

TNL-920

SOL-1, SOL-2, SOL-3

* updating vendor files
* updating class syntax (to new FA-based classes) for all UI elements
* correcting broken tests

SASS compilation variable conventions update, focusing on basic colors, baseline variable usage for padding and margins, ui-depth extends, along with other small fixes. The intent with this is to not have any user-facing impact, and instead move us closer toward having files that use our newer sass conventions.

TNL-1070

TNL-920

Co-authored-by: Greg Price <gprice@edx.org>

OPEN-304

* removing unused font-family-centric Sass variables
* removing unused graphic images and Sass references
* clean up of style removal fallout

TNL-197