Document how to convert sk-learn models to ONNX format

As part of this:

1. Create a simple model in the sk-learn format.
2. Follow the docs at https://onnx.ai/sklearn-onnx/ to convert the model from sk-learn to ONNX.
3. Deploy the model using the OpenVINO serving runtime.
4. Document all the steps you had to go through to convert the model, noting any issues that users may run into

As an outcome of this, we should be able to give a list of steps to the docs team to formally write in the RHODS documents.