Extend pydantic dataclass decorator to add sane defaults for serialization

[lorenzo-w]

• Parse from dict
• Parse from single first constructor argument (if not dict) or tuple of required arguments
• Serialize to single arg or tuple of required args, if all keywords are default
• Serialize to dict otherwise
• Add generic wrapper type for allowing instances or aforementioned representations inside other composite types in Python
• Make it always frozen / immutable
• Use descriptor protocol with different types for getter / setter to accept common mutable types as args during construction (dict, set, list, ...) but save and express them only as matching immutable types (frozendict, frozenset, tuple)
• Have the objects be hashable as long as they don't contain references to non-serializable, local-only resources (data items are serialized to primitives / dicts and globally-accessible resources are serialized to URLs)
• Give the option to generate local hashes, which support referencing of local-only resources but are also only unique & valid locally