[DRAFT] feat: add support for CycloneDX XML

[mcombuechen]

This adds support for CycloneDX XML as an input format. Format detection is being done by introspecting the bytes of the given document.

In addition to this, an abstract SBOMDocument was introduced which will make it possible to add additional SBOM formats (SPDX 2.x, JSON, YAML etc.) later on.

For now, only the ecosystems command has been extended. If this approach is deemed fine I can extend other commands as well.

TODO

• [x] Add copyright headers to sbom package
• [x] Add functionality to all commands processing document input

[garethr]

👍 on the approach here. Good stuff.

[mcombuechen]

cheers @garethr , now ready for review.