Refactor for cleanup
This is mainly a cleanup MR
- rm unused mapping
onSiblingsChange
- rm unnecessary property checks. They should optimize for runtime performance, but the effect is not noticeable. The optimizations e.g. filter out a name change which barely ever happens. Since this somehow destroys OOD and make it hard to refactor SessionModel in later steps, this can be removed.
- rm overdone indirection; use dedicated IntensityDataPropertyWidget instead of general approach. This is the base for the following MRs, still not completely nice therefore.
- rename
IntensityItemPropertyWidget
to what it really is (it's usable and used for any type of items)