Add support for metadata information

[liaoyuan1011]

https://cyclonedx.org/docs/1.4/json/#metadata

[stevespringett]

Yes, there are, but we rely primarily on community contributions. Support for v1.5 (to be released soon) is certainly in scope.

[stevespringett]

Ideally the following metadata should be supported:

• metadata.timestamp
• metadata.lifecycles.phase (requires CycloneDX v1.5 support)
• metadata.tools
• metadata.component