Add validation for array values

[moranegg]

A first step before making the generator a multilingual component, allow the insertion of multilingual values as in the example below when validating codemeta.json file.

{
    "@context": "https://doi.org/10.5063/schema/codemeta-2.0 <https://doi.org/10.5063/schema/codemeta-2.0>",
    "@type" : "SoftwareSourceCode",
    "description": [
      {"@value": "SOFA est...", "@language": "fr"},
      {"@value": "SOFA is...", "@language": "en"},
    ]
}

[progval]

kind of depends on #29