Prompt Class Added

[sadrasabouri]

This PR will add Prompt class with following fields/methods:

Prompt object:

Inputs:

1. message - str - required
2. responses - list of str's - optional (default = [])
3. role - enum - optional - (default = "user")
4. temperature - float - optional - (default = None)
5. model - str - optional - (default = None)
6. date/time - datetime - optional - (default = now)
7. response_obj - dict - optional - (default = None)

Methods:

1. add_response(response, index=None)
2. remove_reponse(index)
3. message() —> return prompt as str that is ready for LLM input
4. to_json() —> return json object of Prompt (like dictionary)

[sepandhaghighi]

@sadrasabouri
Please rename Prompt.py to prompt.py