Handle the case when the Maintainer is not a student

[pradumangoyal]

Currently, implementation of the get_rights_for_semester in the file /utils.rights.py is on the assumption that a maintainer should be a student. But as there can be maintainers with no other roles, it should handle the case too.

My suggestion would be to pass a callback bool (defaults to False) in the function get_rights_for_semester(user, semester_no, right_if_not_student) which should be returned if the user is a maintainer but not a student.

[GopalGupta8216]

assign it to me

[algomaster99]

@GopalGupta8216 feel free to take this up

[pradumangoyal]

@GopalGupta8216 any updates?