Add Enrolled and Completion Rate columns to Courses report

[donnapep]

Describe the solution you'd like

For Reports > Courses, add a column for "Enrolled" with the total # of enrolled students, and replace the current "Completed" column with a "Completion Rate" column. The completion rate is # completed / # enrolled.

Additional context

Note that our # of enrolled students can't be trusted completely right now until we migrate enrollments to a custom table (not just progress). Especially if it is a large site, the background job might be incomplete/disabled so it relies on being calculated on the fly when the user needs it. So this means the calculation isn't guaranteed to be accurate.

Request received via Slack - p1683675681339489-slack-C02P7FHLVR9

[gabrielcaires]

@donnapep Is expected to show the total of enrolled students on all courses?

[gabrielcaires]

@donnapep @burtrw Testing a bit of the required feature, and I found it weird not to have the Completions to compare with enrollments.

What do you think about keeping the completions field?

[burtrw]

Ya, I'm happy to keep Completions. My original worry was we would have too many columns. But it doesn't look too bad. Good to see this!

[burtrw]

nice!