TNL-4906 Subsections now use radio buttons, to allow for "hide after due" as a
visibility option. Also, all tabs have been consolidated to "Basic" and
"Advanced", and visibility options have moved there.

Documentation links are updated to assist course authors with the new
visibility options. Tests have also been updated, and the changes suggested
in TNL-4951 are included.

TNL-4692

TNL-4366
Changes in studio to allow the hide_after_due setting to be utilized.

Includes:
    -python changes to contentstore, where the data is stored.
    -refactoring of timed-examination-preference-editor.underscore, to add this
        setting and make the editor more accessible.
    -javascript changes to link the new setting to the correct data model.
    -sass updates to fix a11y issues on the editor modal.
    -addition of post-due visibility information to course outline in studio.
    -new tests: python, js, acceptance, and a11y

TNL-4366
Changes in studio to allow the hide_after_due setting to be utilized.

Includes:
    -python changes to contentstore, where the data is stored.
    -refactoring of timed-examination-preference-editor.underscore, to add this
        setting and make the editor more accessible.
    -javascript changes to link the new setting to the correct data model.
    -sass updates to fix a11y issues on the editor modal.
    -addition of post-due visibility information to course outline in studio.
    -new tests: python, js, acceptance, and a11y

ECOM-2443

The written style ```interpolate(gettext('some text'), {...}, ...)``` will will cause the string inside gettext() not be extracted.
So a separate line is needed for ```gettext``` when gettext function is directly called inside a call to the interpolate function.

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

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

STUD-2061

STUD-1856

Display "IS VISIBLE TO" when released and published

Reword staff lock prompt and notifications

Change "View Published Version" to "View Live Version"

Change "Unit Tree Location" to "Unit Location in Course"

Switch live content warning based on unpublished changes

Reword discard changes confirmation prompt

Reword unit location tip

Add "Edit the name" popup text for sections and subsections

Fix popup text for section and subsection titles

Add popup text for new section, subsection, and unit buttons

Reword popup for View Live button and add tests

Reword notification when removing staff lock

Update MessageView when has_changes changed

Change "Published" to "Published (not yet released)"

Change "Unpublished (Staff only)" to "Visible to Staff Only"

Fix bok_choy test by changing course separator.
Change format of the modal title to '[Subsection/Section Name] Settings'.
Improve bok_choy test stability.
Studio: correcting modal window size name for outline settings editor
Specify full date in bok_choy tests.
Refactor bok_choy tests.
Remove .modal-editor from basic-modal.underscore
Set classes in modal window dynamically.
Studio: revising outline edit modal tip content and overall size
Rename isEditable to isEditableOnCourseOutline.
Interpolate display name.
Use graded instead of format as flag.
Studio: revising outline settings edit modal size
Fix selectors in bok_choy tests.

Fix failing bokchoy tests

* correcting visual display of outline UI without content
* temporarily resolving page actions that should be hidden by default

* syncing up unit publishing state UI with stateful names/styles
* revising outline item status message display logic to show release status
* fixing publishState value typo in outline UI template
* refining and syncing incontext editor styling
* maintaining visual alignment of collapsed/expanded sections in outline UI
* simplifying page-level action styles on outline UI

STUD-1873

STUD-1726