Add ollama autorun when a server is not available

[pgibler]

This feature would automatically start ollama if a server is not available at the specified listen URL using the listen URL as a startup parameter for the server. Once cmdh has finished executing, if the server was automatically started, the server should be shut down to free resources.

This feature should be toggleable with an environment variable. Also, this feature should be triggered only if a non-chat GPT model is specified.