Export fields `Target` and `Class` as labels

[d-mankowski-synerise]

Hello,
in vulnerability reports created by trivy-operator there are optional report fields, like Target or Class:

  - class: lang-pkgs
    fixedVersion: "1.32"
    installedVersion: "1.25"
    links: []
    primaryLink: https://avd.aquasec.com/nvd/cve-2022-38752
    resource: org.yaml:snakeyaml
    score: 6.5
    severity: MEDIUM
    target: Java
    title: 'snakeyaml: Uncaught exception in java.base/java.util.ArrayList.hashCode'
    vulnerabilityID: CVE-2022-38752

It would be really cool to see a summary in Grafana dashboards what % of vulnerabilities come from OS vs application. It seems like adding these fields to exporter would be as simple as adding two more variables here and here, since these types are defined in Vulnerability struct (although, my golang knowledge is very, very limited).

[stone-z]

Hey @d-mankowski-synerise, sorry for the delay, I somehow overlooked your issue. That does sound like a cool use case, I'll take a look with the team