Expand SecurityScanUtils to Support Snyk

[sam-heilbron]

Background

We support scanning images using various tools, currently Snyk and Trivy. We support Trivy scans with go code defined in this repo, and Snyk scans that are written in bash. It is hard to extend and maintain these tools across all our projects, and so we'd like to consolidate that tooling.

Definition of Done

• Snyk canner works the same way as the trivy scanner (xref: https://github.com/solo-io/gloo-gateway/issues/224)
• Support SBOM generation (xref https://github.com/solo-io/gloo-gateway/issues/223)

This will be filled in more by @rpunia1