feat: reimagine certificate display settings
The course settings `certificate_available_date` (CAD) and
`certificates_display_behavior` (CDB) were previously
acting indedependantly of one another. They now work in
tandem. This change:
- limits CDB to a dropdown
- removes "early_with_info" and adds "end_with_date"
- only takes CAD into account if "end_with_date" is selected
- Moves CDB to the main course schedule settings page
- updates CourseOverview model and CourseDetails objects to
validate these fields and choose sane defaults if they aren't
expected values
This work was previously done in bd9e7dd (complete with bugs), so this
version is toggleable via the ENABLE_V2_CERT_DISPLAY_SETTINGS setting
The course settings `certificate_available_date` (CAD) and
`certificates_display_behavior` (CDB) were previously acting indedependantly
of one another. They now work in tandem. This change:
- limits CDB to a dropdown
- removes "early_with_info" and adds "end_with_date"
- only takes CAD into account if "end_with_date" is selected
- Moves CDB to the main course schedule settings page
- updates CourseOverview to validate these fields and choose sane
defaults if they aren't expected values
Certificates will now show under the following circumstances:
"Immediately upon passing"
certificate_availability_date = null
certificates_display_behavior = "early_no_info"
"End date of course"
certificate_availability_date = null
certificates_display_behavior = "end"
"A date after the course end date"
certificate_availability_date = <date>
certificates_display_behavior = "end_with_date"
