Enable TBD Enrollment Times

[noortor]

Currently, there is no way to have placeholder enrollment times in the courses page when enrollment times are not yet known. This has led to a lot of confusion among students not knowing when they'll be able to enroll in sections. Currently, we set enrollment times that are not known to be an absurdly wrong time so that students infer that the times are not finalized. If enrollment times are not established, they should not show at all or should display as TBD. This will also involve a backend change to enable enrollment times to be blank and ensure that all other current backend systems can handle blank enrollment times.

[mylesfung]

reopen?

[mylesfung]

reopen