Jan: Ollama integration for existing model support

[eckartal]

Overview

• People store models they downloaded from Ollama. In Jan, we should let them run models they already downloaded. This is probably the most commonly asked feature from r/LocalLLaMA.

Goals

• Implement a feature to detect and import Ollama models into Jan

A note

• Plus, we can solve this at Cortex-level: https://github.com/orgs/janhq/discussions/3622
• Cortex is a long-term solution, for quick solutions we should consider Ollama support