Convert existing MIME type based recognition to Type of payload based recognition

MIME types are sometimes different from the actual content. Hence what is downloaded & saved based on that is incorrect.

Hence rewrite the functionality by using the type.

If type is list then there are len(list) no of payloads

if type of payload is string: Then its the actual payload, look at type and save.
If type of payload is list: there are alternate or attachments.