TNL-172: Change type of a previously posted post. IMPORTANT: this commit depends on commit 774887b in cs_comments_service.

TNL-401

[LMS-11372]
[LMS-11370]

TNL-162

The cohort selector is rendered only for a privileged user in a cohorted
course, and that logic is now in an Underscore template instead of Mako.

One minor case is fixed (to pass "" instead of "all" as the group_id
parameter to indicate viewing all threads), and tests are added.

TNL-25

The actions are now consolidated in one location for each piece of
content. Primary actions (vote, follow, endorse, mark as answer) are
buttons, and secondary actions (pin, edit, delete, report, close) are in
a menu. This also includes improved front-end error handling for the
actions and significant test cleanup.

Co-authored-by: jsa <jsa@edx.org>
Co-authored-by: marco <marcotuts@gmail.com>
Co-authored-by: Frances Botsford <frances@edx.org>
Co-authored-by: Brian Talbot <btalbot@edx.org>

This feature is supplanted by the flagged option in the filter menu,
which can work within topics as well as across all topics.

The menu allows filtering to unread, unanswered, or flagged threads.
This includes passing through the appropriate query parameters to the
comments service.

A link to show the comments appears in their place.

Co-authored-by: jsa <jsa@edx.org>

Also change server to pass post type through to the comments service.

The previously existing checkmark for threads with endorsed responses is
removed, as it is mostly redundant.

Responses to question threads can be "marked as answer" instead of
"endorsed".

Co-authored-by: jsa <jsa@edx.org>

Each thread's type is now included in its post details, and question
threads have marked answers shown immediately below the body of the
initial post.

Add help text to several fields, update visual styling, and make it
appear in the right-hand pane of the discussion tab instead of sliding
down from the top.

Co-authored-by: jsa <jsa@edx.org>
Co-authored-by: marco <marcotuts@gmail.com>

FOR-581

FOR-108

This will enable much cleanup of the relevant SASS rules.

The home button is removed, the search box is always displayed, and many
visual adjustments are made, along with a large amount of refactoring.

Originally reviewed in #4211

Thread entries now show an activity count that includes the original
post, and only one of the vote count and activity count is displayed
based on the user's selected sort. The sorting and filtering options now
both use a select and are somewhat more verbose, and the visual styling
of the sort/filter bar is updated.

Originally reviewed in #4165 with a bugfix in #4211

A thread will be labeled if it is pinned, if the user is following it,
or if it was authored by a staff member or community TA. This also
slightly changes the color used for community TA labels.

Originally reviewed in #4072

Use larger and lighter title font, decrease padding, and use lighter
solid backgrounds instead of gradients. Also, refactor SASS code to
conform better to our new style, including using more specific class
names.

Originally reviewed in #4072

FOR-545

Co-authored-by: Brian Talbot <btalbot@edx.org>

JIRA: FOR-591

This commit updates lms/templates.

These keys are now objects with a limited interface, and the particular
internal representation is managed by the data storage layer (the
modulestore).

For the LMS, there should be no outward-facing changes to the system.
The keys are, for now, a change to internal representation only. For
Studio, the new serialized form of the keys is used in urls, to allow
for further migration in the future.

Co-Author: Andy Armstrong <andya@edx.org>
Co-Author: Christina Roberts <christina@edx.org>
Co-Author: David Baumgold <db@edx.org>
Co-Author: Diana Huang <dkh@edx.org>
Co-Author: Don Mitchell <dmitchell@edx.org>
Co-Author: Julia Hansbrough <julia@edx.org>
Co-Author: Nimisha Asthagiri <nasthagiri@edx.org>
Co-Author: Sarina Canelake <sarina@edx.org>

[LMS-2370]

This removes the vote button from threads on the user profile, which was
the only interaction available on the page other than the link to view
the thread in the main discussion view.

JIRA: FOR-429