Support for Factur-X/ZUGFeRD

[gflohr]

As a proof-of-concept, the format Factur-X-Extended has been implemented. You can test it like this:

curl -s -X POST \
        http://localhost:3000/api/invoice/transform-and-create/Factur-X-Extended \
        -F mapping=@contrib/mappings/default-invoice.yaml \
        -F data=@contrib/templates/1234567890-consulting/default-invoice.ods \
        >invoice.pdf

You will find the resulting invoice in invoice.pdf. It validates against the Factur-X/ZUGFeRD specification version 2.3.

The other conformance levels Minimum, Basic WL, Basic, EN16931, and XRechnung will follow suit.