Add API endpoints for new and existing LLMs

[steventangbc]

As the AI landscape is rapidly evolving, many new and emerging LLMs are becoming available to the public. Currently, Anthropic's Claude 3 (Sonnet, Opus, Haiku) leads in many benchmarks and it would be an amazing resource for users if an API endpoint for it could be implemented for this repo. It is notably faster and cheaper than popular LLMs like GPT-4 in terms of token consumption.

[IAmADolphin]

Consider creating a PR for existing ones to illustrate the ask