Add PromptRoles config class for llmInterface

[mohamedryan]

Pull Request Title:
Add PromptRoles config class to LLMInterface for consistent enum handling

Description:
This pull request adds a PromptRoles nested config class to LLMInterface to manage provider-specific enum values.

• Changes Introduced:
  • Added a PromptRoles nested class to LLMInterface.
  • Each concrete class can override this PromptRoles config to define their respective enum values.
  • Updated the controller logic to access promptRoles via the interface instead of relying on specific implementation details.

Reason for Changes:

• Previously, each provider defined its own enums, which were accessed directly, leading to inconsistencies.
• Adding the PromptRoles class to the interface standardizes the access to enums across all providers, ensuring a consistent structure and improving maintainability.

Additional Notes:

• This change enhances the code's readability and structure, providing a clear and predictable interface for interacting with different providers.