Unify gotbot(conversational) model with retrieval(FAQ) and classifier model

[vshan]

I have added the retrieval model and classifier for answering factual questions. Please read this PR: #20 carefully.

To unify all these three models, we can set up a Flask server which serves all the models at three different ports.

Then, one API call which uses three model api endpoints and uses the algorithm mentioned in #20 and answers the user's query.

Finally, the client, like a web application, or a web page simply makes one API call.

Here are all the tasks:

• [ ] Set up a simple Flask server which serves three API endpoints: for conversational model, classifier and retrieval model
• [ ] Add another, global API call, which answers query
• [ ] Make a good chatbot web interface and get chatbot reply from the previous API function

[vshan]

@salman-bhai @SagarB-97 @arvindsaik @raoshashank @hehaichi @viggi-v @aditya5558 guys please go through this and #20