[WIP] simplify the implementation of KeyedContainer
- removed the need for KeyedObjectManager, by keeping the KeyedContainer underlying vector and map directly in KeyedContainer instance.
- ~700 lines of code less
- source compatible with the previous implementation
- old data can be still read
- added move constructor (for GAUDI-1137) and deleted copy constructor
- removed implementations with vector and array random access
KeyedContainer can be further simplified at the price of breaking backward compatibility.
Fixes GAUDI-1138.