Added OpenAI API Integration for Parsing Course Outlines

Closes #16 (closed)

This PR adds functionality to parse tasks from plain text course outlines using the OpenAI GPT-3.5 API.

The following was added:

• Setup OpenAI account and generated API token (added 5$ balance)
• Generated system and user prompts as per #2 (closed)
• Configured dotenv library for API token management
• Used the Ktor library for creating a POST request to the OpenAI API Chat Completions endpoint
• Processed API JSON response to extract task details, outputting a list of Task objects
• Included error handling checks for API token presence, response status, and date formatting issues