Add support for Docker volumes

[mwl]

Something like

mesos:
  resources:
    volumes:
      - hostPath: /foo/bar
        containerPath: /baz/foo/bar
        readonly: false #Optional

and

mesos.resources.volumes[0].hostPath=/foo/bar
mesos.resources.volumes[0].containerPath=/baz/foo/bar
mesos.resources.volumes[0].readonly=false #Optional

[jocatalin]

Your suggested implementation will be sufficient for me have a db cluster with persistent local storage that can restart the db in case of failures.

[jocatalin]

LGTM