Open for course registration

[Daníel Sigurgeirsson]

There should be an API to open for course registration on a given semester. It should accept the semester (which should be a semester sometimes in the future!), start date and end date.

Implementation note: it should save the corresponding values in School_Parameters (the class SchoolConstants maps to it): sStudentRegister, dtStudentReg_Begin and dtStudentReg_End.

Update: Also, there should be an API which returns the current status, i.e. if there is a registration open, and if so, for which semester (and the start and end dates). If not, it should return which semester was the last one open for registration.

In short:

/api/v1/semesters/registration GET - returns info about the current/last registration period

/api/v1/semesters/{semesterid}/registration POST - opens the registration period for the given semester (should be validated!)