feat: Integrate Ollama for local model support.

[eli64s]

Summary

This pull request adds Ollama support via OpenAI compatibility, enabling users to run readme-ai using local model like llama2 and mistral. Additionally, this update includes new CLI options to improve README customization.

Ollama Example

Start by pulling a model such as Llama 2 or Mistral and then start ollama without running the desktop application.

$ ollama pull mistral:latest 
$ ollama serve

Set Ollama local host as an environment variable and run the CLI.

$ export OLLAMA_HOST=127.0.0.1
$ readmeai --api OLLAMA --model mistral --repository https://github.com/eli64s/readme-ai