[Currently work in progress]

Reads and passes custom json payload during upload to be set on the new geonode resource. Should work also for resources which shall be overridden.

This PR contains some fixes/changes of seemingly unrelated parts where errors occured during testing. The proposed changes have to be reviewed and discussed first. Chances are that I missed important parts. However, this PR reveals those locations better than my comment on the related issue.

Referenced ticket: #12862

Checklist

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