Adding MARC21NO version

[pkiraly]

A suggestion comes out of a discussion with Dan Michael O. Heggø.

A new MARC version should reflect that Norwegian public libraries use 6xx$9 to record a language code.

To be added:

MarcVersion:

  MARC21NO("MARC21NO", "MARC21 profile for Norwegian public libraries")

in Tag6xx classes:

    putVersionSpecificSubfields(MarcVersion.MARC21NO, Arrays.asList(
      new SubfieldDefinition("9", "Language code", "NR")
    ));