Refactoring #1484

Updated by pospelov over 3 years ago

* Introduce DetectorContainerItem
* introduce common base DetectorItem for SphericalDetectorItem and RectangularDetectorItem
* move domain detector/instrument generation on board of corresponding items
* move MaskContainer ownership to detector items

* Change ComboProperty: it should store the whole list of available strings.
> Take care of ComboProperty during serialization across the whole project
* Refactor JobItem::JobItemHelper in the context of IntensityData serialization (ComboProperty with units)