Mustang 2.1.1

Mustang 2.1.1 fixes

  • recipient contacts in XRechnung
  • remove outdated dependency
  • allow XRechnung without street
  • only deploy library and validator to maven central, not core nor cli
  • a correction should reference the original invoice via invoiceReferencedDocument, not buyerOrderReferencedDocument
  • upgraded CEN Schematron validation (codes 24) to v1.3.4
  • added unit tests for ubl conversion and visualization
  • and adds the possibility to specify a seller order referenced document