Add posibility to specify a list of volumes to inherit from another container

Merged username-removed-356725 requested to merge Bevaz/gitlab-ci-multi-runner:volumes-from into master

Introduce new parameter in docker section of config.toml. Detailed explanation of parameters can be found in docker manual

  • volumes_from - A list of volumes to inherit from another container. Specified in the form <container name>[:<ro|rw>]

Example:

[runners.docker]
  volumes_from = ["storage_container:ro"]