add basic test and defaults

add a basic end to end test - creating the pod, and validating the paths for the driver and in requested pod
make the client argument defaults come from the oras and driver packages in case need to be used elsewhere
with the test (and in the docs) added an example for how to use the driver locally with MiniKube (e.g., build the image, load, and set imagePullPolicy to Never
fixed a bug in docs link (had an extra github.com)
briefly tested the sanity-test, and didn't totally get the setup, will come back to this if needed!

converged-computing / oras-csi