Chat mode

For the models: gpt-4 and gpt-3.5-turbo

You must replace:

• The OpenAI_APIKey with yours.
• The Model you want to use, for example, gpt-4.
• The Messages with a list of MessageItems. Where you set the roles (system, user, and assistant) and their contents (messages). I suggest to have a maximum of 5 to 6 conversations in memory.