The advisory sources that are not updated should be stored in a common repo and imported from federatedcode-style

[TG1999]

We have few examples of pipelines/importers like:

• https://github.com/RetireNet/Packages/

• VCIO-API-V2: Migrate Retiredotnet importer to advisory V2 #2039

These kind of importer's data is not updated often, instead of importing this data on regular basis, these advisories should all be stored in a common repo that we can import from federatedcode-style.

We should change these advisories into our standard JSON format, and store them in a common repo.