Forward the docker registry password environment variables to the docker runner

[tkilias]

Background:

• CI processes, might use the following environment variables to supply the passwords for the docker registry

  TARGET_DOCKER_PASSWORD
  SOURCE_DOCKER_PASSWORD
  

• The docker runner currently, doesn't forward these

Rationals

• We could use docker run --env or docker run --env-file to provide the environment variables
• Because these environment variables are password the file is the better option, because it is less likely we leak them from there to the stdout