Implement Austrian CDA generation

[ajungwirth]

• Implement CDA generator for:
  • EMS (https://art-decor.org/decor/services/ProjectIndex?prefix=epims-&format=html&language=&ui=en-US)
  • ELGA e-Impfpass (https://art-decor.org/decor/services/ProjectIndex?prefix=elgaimpf-&format=html&language=&ui=en-US)
  • ELGA CDA (https://art-decor.org/decor/services/ProjectIndex?prefix=elga-&format=html&language=&ui=en-US)
  • ELGA Patient Summary (https://art-decor.org/decor/services/ProjectIndex?prefix=elgaps-&format=html&language=&ui=en-US)