Referencing code lists in JSON export

[pkiraly]

code lists should be reorganize so that they should be references.

Originally posted by @pkiraly in https://github.com/pkiraly/qa-catalogue/issues/45#issuecomment-1782642514

[pkiraly]

@nichtich @timathom I have implemented what Jakob suggested, but I have two notes:

• there are code list which are reused, and code lists which appear only once. In this iteration I move the reused code lists to the codelists section. Those which occur only once remained in their original place.
• the codelists section appears at the end of the file. Is it OK, or should it appear at the beginning of the file?
• some code list have a name, such as "MARC Code List for Countries". I did not add it now. Does Avram enable to put it? (I did not add now).

An example:

    "013": {
      ...
      "subfields": {
        ...
        "b": {
          "label": "Country",
          "repeatable": false,
          "codes": "https://www.loc.gov/marc/countries/countries_code.html"
        },
        ...
      }
    }

then the codelist might be a pure list of codes

  "codelists": {
    "https://www.loc.gov/marc/countries/countries_code.html": {
      "aa": {
        "label": "Albania"
      },
      "abc": {
        "label": "Alberta"
      },
        ...
      }
    }

or it might have additional metadata, such as a name:

  "codelists": {
    "https://www.loc.gov/marc/countries/countries_code.html": {
      "name": "MARC Code List for Countries",                 ← here is the name of the code list 
      "codes": {
        "aa": {
          "label": "Albania"
        },
        "abc": {
          "label": "Alberta"
        },
        ...
      }
    }

[nichtich]

Having only some codelists under codelists is ok and the position of this key does not matter as JSON knowns no key order. The extension of referenced codelists with metadata makes sense. This requires a breaking change in Avram specification but its worth to do. See https://github.com/gbv/avram/issues/37