Refactor/creating llm package

[luillyfe]

LLM Package Refactoring: Modular and Extensible Language Model Integration

Overview
This PR introduces a significant refactoring of our Language Model integration, creating a modular and extensible package for easely swapping between different LLM providers.

Key Changes

1. Introduced a LanguageModel interface in llm/main.go to standardize LLM interactions.
2. Implemented Anthropic support in anthropic_client.go
3. Added Mistral support in mistral_client.go
4. Abstracted common LLM functionality to allow for easy addition of new providers.

Detailed Changes
1. LanguageModel Interface

• Created a new interface in llm/main.go that defines a common GenerateText method for all LLM implementations.

2. Anthropic Implementation

• Refactored existing anthropic integration into AnthropicLLM struct in anthropic_client.go
• Implemented the LanguageModel interface for Anthropic.
• Adding configurability for model selection.

3. Mistral Implementation

• Added new MistralLLM struct in mistral_client.go to support Mistral's LLMs.
• Implemented the LanguageModel interface for Mistral.
• Included model selection and default configurations.

Benefits

• Modularity: Each LLM provider is encapsulated in its own struct and file.
• Flexibility: Easily swap between different LLM provider or add new ones.
• Consistency: Standardized interface for all LLM interactions.
• Extensibility: Simple process to add new functionality across LLMs.

var llm LanguageModel
llm = NewAnthropicLLM("") // or NewMistralLLM("")
response, err := llm.GenerateText(context.Background(), "Your prompt here")