option for the user to specify URL

Ollama is a server, and it can be run from other machines, so we should specify an option for the user to choose their ollama URL.

We should parse this url to make sure it's got the protocol (http://) and the port (usually :11434) if they're lacking. This adds more functionality for users with "home labs" or employees in corporations that are hosting their own fine-tuned AI on their servers.