Better studyfield management

[ShootingStar91]

Studyfields get outdated and some programmes may end up having a cluttered list of studyfields to choose from. May not be a big deal, but when the names are similar like "Biostatistics and bioinformatics" and "Biostatistics", user may choose the wrong one causing possible issues. Therefore, there should be a way to filter out the old ones. Possible ways is to check from importer which ones are relevant, or at least to let someone adjust them by hand from UI.

The same goes to programmes and their changing names.