Use of container secrets needs amending about oci-oracle-xe

[gvenzl]

Hi @martincarstenbach,

Thanks a lot for this great write-up on how to use secrets with Docker. After some research, I found that the different containerization technologies use rather different approaches for handling secrets (Docker, Podman, Kubernetes).

I feel that the ReadMe for these images on how to use them is not the right place to educate people on how the secrets mechanism in all the different containerization technologies works. Also because Docker Hub has a 20k character limit for the ReadMe as I found out some months ago. I have therefore opted for linking to the official documentation of said three containerization technologies above, rather than documenting the details on how to create and use secrets for all three technologies.

Thx,