[Class statistics] Any degree programme as a combined programme

[valtterikantanen]

Currently it's possible to choose only one combination of one specific bachelor's programme and one master's (licentiate) programme for eläinlääkis. We should expand the functionality so that the user is able to choose any programme and

• if it's a bachelor's programme, show all students who have continued to any master's programme (in the same study right)
• if it's a master's programme, show all students who have continued from any bachelor's programme (in the same study right)

The goal is to offer a better understanding how students' complete study path looks like.

• Start time in master's programmes credit accumulation must be the start time of each student in bachelor's programme (if there's one). It doesn't matter if the students don't have the same start time