Allow configuration of Ollama base URL

[bkrabach]

Enable the configuration of the Ollama base URL through an environment variable, providing flexibility for different deployment scenarios, such as a remote-hosted Ollama server.

[github-actions]

All contributors have signed the CLA ✍️ ✅
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[bkrabach]

I have read the CLA Document and I hereby sign the CLA

[bkrabach]

@ymichael it appears the cla-signatures branch is not set up on your fork, so it will not pass the CLA Assistant action? Would you be willing to make the requested change to support reading the environment variable for setting the Ollama endpoint? I appreciate the work you did to provide Ollama support in general, this change will let folks use it when running their Ollama service on another host.

[ymichael]

thanks! (separately I removed the CLA check from this repo here: 783bca0)