Right now only the name and the docker image can be defined, but with
the help of the pod_environment_configmap parameter arbitrary
environment variables can be passed to the sidecars.
To improve the documentation we need to split it into smaller parts:
* quickstart (in the readme)
* general concepts
* tutorials
* how to
* references
And then add the missing information. So far I just split the existing
documentation and left references almost empty. I assume that references
may duplicate the rest of the documentation in a way that the doc will
have references to this section, that contains all the formal details.