fix: llama helper for text to summary, api helpers ip

[rockett-m]

This pull request introduces updates to the backend utilities and environment configuration to enhance API connectivity and model querying capabilities. The most important changes include the addition of new helper modules for Cerebras and Llama API connections, updates to environment variables, and error handling improvements.

Environment Configuration:

• Added LLAMA_MODEL=llama3.1-8b to the .env.example file to specify the default Llama model.

Cerebras API Integration:

• Created backend/utils/cerebras_connect.py to handle connections and queries to the Cerebras API, including error handling and response extraction.

Llama API Integration:

• Added backend/utils/llama_api_helpers.py to provide helper functions for tokenization, API calls, and cost estimation for Llama models.

Modal API Integration:

• Introduced backend/utils/modal_connect.py to facilitate connections to the Modal API, including environment setup and package installations.