Configurable modelcourses list for admin add course

[taniwallach]

This is intended to supplement what was just done as a hot fix in #1447 but to make it possible to configure a list of model courses which get prepended to the provided list.

[drgrice1]

I am not sure that this qualifies for a hotfix. This adds a new feature that was not present before. Generally that is something that should not be added after the release.

[taniwallach]

Yes and no. In the past - just about any directory in the courses directory could be used as a the source of the templates directory, as listCourses included them (so long as they avoided some regular expression conditions). This provides an option to optionally define selected directories (other than the fixed modelCourse) to be included in the list. So it reenables more of the prior functionality, but in a controlled manner.

It can certainly be put in develop instead (or dropped). Whatever the team prefers.

[pstaabp]

I think this looks good. Technically not a hot fix, but functionality nearly equivalent and more flexible.

[drgrice1]

I see. I suppose that could be hotfix worthy if that is something that was commonly utilized. What do others thing on this?

[drdrew42]

This does give an alternative for the options that were available before listCourses was modified.

[drgrice1]

Okay. A hotfix it can be then.

[drgrice1]

I will merge and also add it to develop.