Add A Docker Sample

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Docker can be a bit daunting if you have never used it before.

Add a Docker sample that clearly shows a deployment process involved creating your own docker image.
e.g.

• creating self-signed certificates and a note about how to do it outside of simple demos
• connecting to a bootstrapped network
• best practices of which directories should be mounted

https://docs.corda.net/docs/corda-os/4.8/docker-image.html