Update to Python 3.8 and improve type hints

[russellkan]

Python 3.8 supports TypedDict, defined in PEP 589. We should use this to improve the type hints for the dictionaries used to represent objects in the various JSON files.

Example:

class CiodModuleDict(TypedDict):
    ciodId: str
    moduleId: str
    usage: str
    conditionalStatement: Optional[str]
    informationEntity: str