Cross-Ref stored as a string when it could be a structured map

[goneall]

currently, the cross-ref is a string which internally uses a JSON object format. When serialized, it currently looks as follows:

"crossRef": [
    "{url: https://joinup.ec.europa.eu/page/eupl-text-11-12,isValid: true,isLive: false,isWayBackLink: false,match: false,timestamp: 2020-09-04 - 15:25:56}",
    "{url: https://joinup.ec.europa.eu/sites/default/files/custom-page/attachment/eupl_v1.2_en.pdf,isValid: true,isLive: true,isWayBackLink: false,match: false,timestamp: 2020-09-04 - 15:25:58}"
  ],

This could be serialized as an object which would make it more usable by the reader:

"crossRef": [
    {"url: https://joinup.ec.europa.eu/page/eupl-text-11-12",isValid: true,isLive: false,isWayBackLink: false,match: false,timestamp: "2020-09-04 - 15:25:5},
    {"url: https://joinup.ec.europa.eu/sites/default/files/custom-page/attachment/eupl_v1.2_en.pdf",isValid: true,isLive: true,isWayBackLink: false,match: false,timestamp: "2020-09-04 - 15:25:58"}",
    "{url: https://joinup.ec.europa.eu/sites/default/files/inline-files/EUPL%20v1_2%20EN(1).txt,isValid: false,isLive: false,isWayBackLink: false,match: --,timestamp: 2020-09-04 - 15:25:59}
  ],

[goneall]

Resolved in PR #82