Add Photon OS importer pipeline #1586

[Shivaay26]

Fixes #1586

Summary

Add an importer pipeline for Photon OS security advisories using the
OSV-format feed republished at https://github.com/captn3m0/photon-os-advisories

Changes

• Add PhotonOSImporterPipeline in vulnerabilities/pipelines/photon_os_importer.py
• Register pipeline in vulnerabilities/importers/__init__.py
• Add unit tests and test data in vulnerabilities/tests/

Notes

• Uses PHSA ID as the only alias to avoid cross-version alias conflicts
  since the same CVE appears in separate advisories for each
  Photon OS version (3.0, 4.0, 5.0)
• CVEs stored as references instead of aliases to preserve the data
• Handles inconsistent ranges format (dict vs list) present in upstream data
• Deduplicates affected package entries — same purl appears multiple
  times per advisory with and without version data

[ziadhany]

@Shivaay26, we already have an OSV parser, so there's no need to implement one from scratch.

also , It looks like the data from this source is just auto-generated from other sources,
https://github.com/captn3m0/photon-os-advisories/blob/main/generate.py

I think we should handle Photon OS by following the implementation in this PR: https://github.com/aboutcode-org/vulnerablecode/pull/2198

I really appreciate the effort and thanks for giving this a try!.

[Shivaay26]

Thanks a lot for the detailed comment.

And I didn't know that new pr already exists, so it was my fault.