hash integrity of the scanned image

**What would you like to be added**: Add integrity verification to SBOMs ref: https://cyclonedx.org/use-cases/#integrity-verification

**Why is this needed**:
This is beneficial to verify the integrity of the image via multiple supported methods.

**Additional context**:

No files, tests, or entry points are named. Start with the linked CycloneDX integrity-verification use case and review how Syft represents SBOMs for container images; done should include defined supported verification methods and integrity information in the generated SBOMs.

Written by the indexing model from the issue text.