Issue 246 fix, type hints for object schema dict output class values improved

[spacether]

Issue 246 fix

• converts ApiResponses back to dataclasses to fix mypy errors when accessing properties in them
  • removes defaults except for ApiResponseWithoutDeserialization
• removed format property from schemaType CodegenSchema
• makes schema addition use the most permissive information because addition is used to generate mapValueSchema
• adds java tests of mapValueSchema.types which the python code uses to determine if casting is needed for properties

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