Update documentation to access logs from image / environment build

[Pierre Poulain]

The build of some environment may fail. We need to access logs for post-mortem/build analysis and further improvement of the environment.

We should update documentation to reflect this.

[Pierre Poulain]

Strategy to access Docker logs could be:

docker ps -a

To find stopped Docker container and get the relevant id.

Then look at corresponding logs:

docker logs <container-id>