PropertySet improvements

improve memory usage (preset list and hasmap sizes, store fewer references to parent objects)
deprecate ability to detach - should always be attached to PropertyTree
fix issue with messed up index of Property
deprecate countAncestors it is just number of path elements
verify that PropertySet is attached to a correct PropertyTree (before it was possible to add a foreign PropertySet)
Deprecate Value.isSet as Value.isPropertySet already exists
Remove dead code in Json to PropertyTree/Set Translators
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enonic / xp