Update VirtualCorpusRewrite Remove Owner

[margaretha]

Named virtual corpora are system corpora that are cached by filenames.

When searching a named VC with a username, for instance:

referTo "system/ratskorpus"

Kustvakt rewrites the query as follows

{
    "@type": "koral:docGroupRef",
    "ref": "ratskorpus",
    "rewrites": [
        {
            "@type": "koral:rewrite",
            "operation": "operation:deletion",
            "scope": "ref(system/ratskorpus)",
            "src": "Kustvakt"
        },
        {
            "@type": "koral:rewrite",
            "operation": "operation:insertion",
            "scope": "ref(ratskorpus)",
            "src": "Kustvakt"
        }
    ]
}

The rewrites should be merged with operation:override.

{
  "@type" : "koral:rewrite",
  "src" : "Kustvakt",
  "origin" : "Kustvakt",
  "operation" : "operation:override",
  "scope" : "ref",
  "source" : "system/ratskorpus"
}

For the future, the cache keys should be enhanced with username instead, so we can support caching users VC as well.

[Akron]

Sounds reasonable. I guess you mean system/ratskorpus instead of system/named-vc1 in the last snippet.

[margaretha]

Yes, I have updated the issue description.

[margaretha]

I have added a new issue #784 to remind us about the improvement of VC-cache structure with usernames.