Add EmptyDir volumes for new-app containers

[mnagy]

Modifies new-app so it defines volumes and volume mounts for containers based on volumes defined in docker images. Created volume sources are EmptyDir. Currently, the naming scheme is "containerName-volume-1".

For this to work and not break new-app with our images, #3037 must be merged first.

Example with json modified for brevity:

$ osc new-app --docker-image=openshift/mysql-55-centos7 -o json
{
    "kind": "List",
    "apiVersion": "v1",
    "metadata": {},
    "items": [
        {
            "kind": "DeploymentConfig",
            "apiVersion": "v1",
            "metadata": {
                "name": "mysql-55-centos7",
                "creationTimestamp": null
            },
            "spec": {
                "template": {
                    "spec": {
                        "volumes": [
                            {
                                "name": "mysql-55-centos7-volume-1",
                                "emptyDir": {},
                                "rbd": null
                            }
                        ],
                        "containers": [
                            {
                                "name": "mysql-55-centos7",
                                "image": "openshift/mysql-55-centos7:latest",
                                "volumeMounts": [
                                    {
                                        "name": "mysql-55-centos7-volume-1",
                                        "mountPath": "/var/lib/mysql/data"
                                    }
                                ]
                            }
                        ]
                    }
                }
            },
        }
    ]
}

Fixes #2929

[mfojtik]

[test]

[openshift-bot]

continuous-integration/openshift-jenkins/test SUCCESS (https://ci.openshift.redhat.com/jenkins/job/test_pull_requests_origin/3088/)

[mnagy]

Added & modified tests, thanks @Kargakis for help! PTAL

[0xmichalis]

Use this constant here

[mnagy]

This can go in after review and #3037

[0xmichalis]

LGTM on green

[openshift-bot]

Evaluated for origin up to 4ca7271

[mnagy]

Only assets test fails, unrelated to this PR.

@smarterclayton your approval please?

[smarterclayton]

Unicode symbols can blow up user's editors. Let's avoid them in our codebase.

[mnagy]

Closing in favour of #3098 since it encompasses this change and adds the warning.