Add documentation on how to use the Docker images

[PierreZ]

The issue is related to apple/foundationdb#5717. We should add some documentation on:

1. how-to use the build image:
   • to build FDB,
2. how-to use the devel image, to use:
   • vscode server,
   • joshua(I wonder if we should document this here or on the joshua repo, which also needs some documentation 🤔),
3. how-to use the distcc image, to use:
   • distcc,
4. how-to use the codebuild image.

I would love to help on this(and also on Joshua's documentation), but I'm only familiar with the build image for now.

[ammolitor]

I'll add a doc to the repo explaining this, thanks for the suggestion.

[ammolitor]

Updated the README.md with descriptions. Any further documentation should go in the README.md in the main foundationdb repo