Reporting: License report in machine-readable form

[gernot-h]

For post-processing like attaching a Web UI, separate consistency checks against upstream packages etc. we would need a machine-readable variant of License Report (JSON/XML/YAML/you name it) which would include all information as described in #376 - #380.

@tngraf has worked on a draft for an XML-based format (PLIX), maybe this would be a good starting point?

[mcjaeger]

well technically, xhtml is aso machine readable in that sense. I think we should go for SPDX export first for what can be handed over to the customer. (and maybe PLIX for internal use)