* Updates endpoint from v1/completions to v1/chat/completions
* Add SharpTokens as a library to calculate input token usage
* Subtract input tokens from max_tokens to ensure the API tokens don't exceed the max specified
* Add Chat history support since this API supports it
* Add a personality prompt to tweak the way the bot behaves
* Add a min_tokens config to increase the quality of chat messages when history is enabled
* Adjust the response function to throw an exception so that a null message isn't added to the list.
