Change artifact identification.

[soffokl]

Now we have duplicates of some fields that confusing people.
Artifact should be identified like user/filename or just hash.
public or private scope in ID is useless. If user is not authorized he should see only public artifacts. If user using token for request he should see all artifacts allowed to him.

{
    "md5Sum": "5d72cdcaa2092e4ff013a0eb06039291",
    "id": "public.5d72cdcaa2092e4ff013a0eb06039291",
    "ownerFprint": "public",
    "owner": ["public"],
    "parent": "openjre7",
    "name": "hadoop",
    "size": 46300982,
    "version": "4.0.0"
}

[soffokl]

Merged to production.