Include ability to add a new course to existing members

[kimwhite]

Is your feature request related to a problem? Please describe.
New Members are Enrolled in the assigned courses at checkout.
When a new course is added to the site, existing members are not auto-enrolled in the new course.
The only way to do this now is to add each user manually.

Describe the solution you'd like
Provide an "option" on the course page to ‘enroll’ current members of that level in the course.

Describe alternatives you've considered
Checkbox on Course, script to run on backend, ??

Additional context
There may be cases when site owners do not want users to be enrolled, so the ability to do this should be optional and not by default.