refactor similar List Entry classes into new ListEntry class (!33) · Merge requests · Jonathan-Sebastian Halmen / WS2020_PS_SWA_2_4

This cleans up the models somewhat

we have 3 classes connecting one Media to one User:

this extracts their commonalities into ListEntry.

This also means that we don't need separate Id-classes for them anymore. There's now one ListEntryId used by all of them.

refactor similar List Entry classes into new ListEntry class