[Docs]: Add more documentation on container usage

[timheuer]

Describe the bug

The docs are targeted more at direct building/consuming of the binaries and lacking on usage/configuration of the container image. There also is no clear table-of-contents section that speaks to the container image.

Try to find information about typical run and/or configuration options of the container image.

Expected Docs

• [ ] A section in the doc of getting started only with the container image that covers typical run/start commands in docker
• [ ] Section in configuration of any/all environment variables that can be set on the container image that map to any of the garnet.conf settings

[Zerotask]

Additionally it would be great to have some more information about using Garnet in Kubernetes (e.g. in combination with helm charts)