rm VectorDescriptor

VectorDescriptors are completely removed and replaced by VectorProperty

Steps of Descriptor refactoring:

1. reduce usage of non-default functional pointers set() and get()
2. move Descriptor functionality to Property
3. use Property instead of Descriptor
4. remove Descriptor from code
5. refactor serialization of Property
6. replace Property macro definitions like DOUBLE_PROPERTY(intensity, Intensity) by explicit member with setter and getter

This MR does (2,3,4) for VectorDescriptor and (2) for DoubleDescriptor