add property `cdx:reproducible`

[jkowalleck]

Purpose: flag a SBOM document or parts of it as reproducible. reproducible SBOMs usually omit time-and random-based information, and might render elements in a reproducible order.

some implementations that can generate “reproducible” BOMs, by omitting time- and random-based values, ordering elements, and so on already exist.

• https://github.com/CycloneDX/cyclonedx-maven-plugin
• https://github.com/CycloneDX/cyclonedx-php-composer
• https://github.com/CycloneDX/cyclonedx-webpack-plugin
• https://github.com/CycloneDX/cyclonedx-node-npm

caused by https://github.com/CycloneDX/cyclonedx-property-taxonomy/pull/69#issuecomment-1667631922

[jkowalleck]

@stevespringett could I get your opinion on this proposed property?