Readme: Getting Started Section

[cherrywoods]

The Getting Started section of the README contains a link to an example which has moved or no longer exists: https://github.com/google/jaxonnxruntime/blob/main/examples/imagenet/imagenet_main.py.

[jsilter]

The only example I could find was in docs/examples, and it was extremely minimal. More (and more complex) examples would be helpful.