Add holdings to GUI of publications that are electronical or are supervolumnes

[TobiasNx]

If your look at the detail page of a single publication that is electronical or otherwise has no physical item information the holding is not listed. Therefore you cannot see if an institution has access to a certain publication without looking at the json file.

"hasItem": [
    {
      "type": [
        "Item",
        "DigitalDocument"
      ],
      "label": "Electronic Portfolio",
      "electronicLocator": ["https://eu04.alma.exlibrisgroup.com/view/uresolver/49HBZ_DUE/openurl?u.ignore_date_coverage=true&portfolio_pid=53738940520006441&Force_direct=true"](https://eu04.alma.exlibrisgroup.com/view/uresolver/49HBZ_DUE/openurl?u.ignore_date_coverage=true&portfolio_pid=53738940520006441&Force_direct=true),
      "sublocation": ["https://hbz-network.userservices.exlibrisgroup.com/view/uresolver/49HBZ_DUE/openurl?u.ignore_date_coverage=true&rft.mms_id=990134555090206441"](https://hbz-network.userservices.exlibrisgroup.com/view/uresolver/49HBZ_DUE/openurl?u.ignore_date_coverage=true&rft.mms_id=990134555090206441),
      "heldBy": {
        "id": ["http://lobid.org/organisations/DE-61#!"](http://lobid.org/organisations/DE-61#!),
        "isil": "DE-61",
        "label": "Universitäts- und Landesbibliothek Düsseldorf"
      },
      "id": ["http://lobid.org/items/990134555090206441:DE-61:53738940520006441#!"](http://lobid.org/items/990134555090206441:DE-61:53738940520006441#!)
    },
    {
      "type": [
        "Item",
        "DigitalDocument"
      ],
      "label": "Electronic Portfolio",
      "electronicLocator": ["https://eu04.alma.exlibrisgroup.com/view/uresolver/49HBZ_ULB/openurl?u.ignore_date_coverage=true&portfolio_pid=53738940520006441&Force_direct=true"](https://eu04.alma.exlibrisgroup.com/view/uresolver/49HBZ_ULB/openurl?u.ignore_date_coverage=true&portfolio_pid=53738940520006441&Force_direct=true),
      "sublocation": ["https://hbz-network.userservices.exlibrisgroup.com/view/uresolver/49HBZ_ULB/openurl?u.ignore_date_coverage=true&rft.mms_id=990134555090206441"](https://hbz-network.userservices.exlibrisgroup.com/view/uresolver/49HBZ_ULB/openurl?u.ignore_date_coverage=true&rft.mms_id=990134555090206441),
      "heldBy": {
        "id": ["http://lobid.org/organisations/DE-5#!"](http://lobid.org/organisations/DE-5#!),
        "isil": "DE-5",
        "label": "Universitäts- und Landesbibliothek Bonn"
      },
      "id": ["http://lobid.org/items/990134555090206441:DE-5:53738940520006441#!"](http://lobid.org/items/990134555090206441:DE-5:53738940520006441#!)
    },
    {
      "type": [
        "Item",
        "DigitalDocument"
      ],
      "label": "Electronic Portfolio",
      "electronicLocator": ["https://eu04.alma.exlibrisgroup.com/view/uresolver/49HBZ_DUE/openurl?u.ignore_date_coverage=true&portfolio_pid=53738940540006441&Force_direct=true"](https://eu04.alma.exlibrisgroup.com/view/uresolver/49HBZ_DUE/openurl?u.ignore_date_coverage=true&portfolio_pid=53738940540006441&Force_direct=true),
      "sublocation": ["https://hbz-network.userservices.exlibrisgroup.com/view/uresolver/49HBZ_DUE/openurl?u.ignore_date_coverage=true&rft.mms_id=990134555090206441"](https://hbz-network.userservices.exlibrisgroup.com/view/uresolver/49HBZ_DUE/openurl?u.ignore_date_coverage=true&rft.mms_id=990134555090206441),
      "heldBy": {
        "id": ["http://lobid.org/organisations/DE-61#!"](http://lobid.org/organisations/DE-61#!),
        "isil": "DE-61",
        "label": "Universitäts- und Landesbibliothek Düsseldorf"
      },
      "id": ["http://lobid.org/items/990134555090206441:DE-61:53738940540006441#!"](http://lobid.org/items/990134555090206441:DE-61:53738940540006441#!)
    },
    {
      "type": [
        "Item",
        "DigitalDocument"
      ],
      "label": "Electronic Portfolio",
      "electronicLocator": ["https://eu04.alma.exlibrisgroup.com/view/uresolver/49HBZ_ULB/openurl?u.ignore_date_coverage=true&portfolio_pid=53738940540006441&Force_direct=true"](https://eu04.alma.exlibrisgroup.com/view/uresolver/49HBZ_ULB/openurl?u.ignore_date_coverage=true&portfolio_pid=53738940540006441&Force_direct=true),
      "sublocation": ["https://hbz-network.userservices.exlibrisgroup.com/view/uresolver/49HBZ_ULB/openurl?u.ignore_date_coverage=true&rft.mms_id=990134555090206441"](https://hbz-network.userservices.exlibrisgroup.com/view/uresolver/49HBZ_ULB/openurl?u.ignore_date_coverage=true&rft.mms_id=990134555090206441),
      "heldBy": {
        "id": ["http://lobid.org/organisations/DE-5#!"](http://lobid.org/organisations/DE-5#!),
        "isil": "DE-5",
        "label": "Universitäts- und Landesbibliothek Bonn"
      },
      "id": ["http://lobid.org/items/990134555090206441:DE-5:53738940540006441#!"](http://lobid.org/items/990134555090206441:DE-5:53738940540006441#!)
    },
    {
      "type": [
        "Item",
        "DigitalDocument"
      ],
      "label": "Electronic Portfolio",
      "electronicLocator": ["https://eu04.alma.exlibrisgroup.com/view/uresolver/49HBZ_DUE/openurl?u.ignore_date_coverage=true&portfolio_pid=53738940500006441&Force_direct=true"](https://eu04.alma.exlibrisgroup.com/view/uresolver/49HBZ_DUE/openurl?u.ignore_date_coverage=true&portfolio_pid=53738940500006441&Force_direct=true),
      "sublocation": ["https://hbz-network.userservices.exlibrisgroup.com/view/uresolver/49HBZ_DUE/openurl?u.ignore_date_coverage=true&rft.mms_id=990134555090206441"](https://hbz-network.userservices.exlibrisgroup.com/view/uresolver/49HBZ_DUE/openurl?u.ignore_date_coverage=true&rft.mms_id=990134555090206441),
      "heldBy": {
        "id": ["http://lobid.org/organisations/DE-61#!"](http://lobid.org/organisations/DE-61#!),
        "isil": "DE-61",
        "label": "Universitäts- und Landesbibliothek Düsseldorf"
      },
      "id": ["http://lobid.org/items/990134555090206441:DE-61:53738940500006441#!"](http://lobid.org/items/990134555090206441:DE-61:53738940500006441#!)
    },
    {
      "type": [
        "Item",
        "DigitalDocument"
      ],
      "label": "Electronic Portfolio",
      "electronicLocator": ["https://eu04.alma.exlibrisgroup.com/view/uresolver/49HBZ_ULB/openurl?u.ignore_date_coverage=true&portfolio_pid=53738940500006441&Force_direct=true"](https://eu04.alma.exlibrisgroup.com/view/uresolver/49HBZ_ULB/openurl?u.ignore_date_coverage=true&portfolio_pid=53738940500006441&Force_direct=true),
      "sublocation": ["https://hbz-network.userservices.exlibrisgroup.com/view/uresolver/49HBZ_ULB/openurl?u.ignore_date_coverage=true&rft.mms_id=990134555090206441"](https://hbz-network.userservices.exlibrisgroup.com/view/uresolver/49HBZ_ULB/openurl?u.ignore_date_coverage=true&rft.mms_id=990134555090206441),
      "heldBy": {
        "id": ["http://lobid.org/organisations/DE-5#!"](http://lobid.org/organisations/DE-5#!),
        "isil": "DE-5",
        "label": "Universitäts- und Landesbibliothek Bonn"
      },
      "id": ["http://lobid.org/items/990134555090206441:DE-5:53738940500006441#!"](http://lobid.org/items/990134555090206441:DE-5:53738940500006441#!)
    },
    {
      "label": "lobid Bestandsressource",
      "type": [
        "Item",
        "NurTitel"
      ],
      "heldBy": {
        "id": ["http://lobid.org/organisations/DE-61#!"](http://lobid.org/organisations/DE-61#!),
        "isil": "DE-61",
        "label": "Universitäts- und Landesbibliothek Düsseldorf"
      },
      "id": ["http://lobid.org/items/990134555090206441:DE-61:990016603550206443#!"](http://lobid.org/items/990134555090206441:DE-61:990016603550206443#!)
    }
  ],