LEARNER-1894
This commit adds in course messaging for three use cases. First,
when the user is not signed in, the user is shown a message that
provides a link to sign in or register. If the user is signed in
but not enrolled, they are given a link to do so. If the user is
enrolled but the course has not yet started, they are shown a
message explaining when the course starts and shown a link (not
yet enabled) to add a reminder to their calendar.
The implementation defines a base message class and extends it
for the course home messages as well as the previously implemented
page level messages.
LEARNER-1628
This allows enrolled users to write reviews on the reviews page that
can be accessed through the course tools sidebar. A button in the top
corner of the page toggles the widget that is configured with a
setting in the common.py file. The reviews tool is Course Talk.
This sock sits at the bottom of both the home and the course content pages. It allows the user to click a 'Learn More' button to open a panel that allows the user to navigate to the upgrade checkout page. The sock is only shown for users that have not yet upgraded in a course that has a verification upgrade date that has not yet passed. Python tests cover the various course mode and upgrade dates.
