Deprecate RHELv2PackageInfo

[RTann]

There has only been a single RHELv2Package per RHELv2PackageInfo since Scanner 2.19.0 (see #456 for the related PR). Because of this, there is no real need for RHELv2PackageInfo any longer, so this PR deprecates it and removes all current usages of it. It is still required to exist to ensure we correctly diff older genesis dumps correctly. See the related changes in cmd/updater/diffdumps/rhelv2_diff.go.

Let's look at the two cases when we'd populate a RHELv2Vulnerability:

1. Vuln dump generation
   • You can see here, for each criterion, we create a new RHELv2PackageInfo and add only a single RHELv2Package
2. Vuln retrieval from the DB
   • You can see here, we only add a single RHELv2Package, pkg, to the single RHELv2PackageInfo entry for the vuln.

This PR deprecates RHELv2PackageInfo, adds the two fields FixedInVersion and ArchOperation to RHELv2Package, and ensures compatibility with previous genesis dumps by converting the old RHELv2PackageInfo into a modern RHELv2Package

[ghost]

Images are ready for the commit at 70c7be8.

To use the images, use the tag 2.26-62-g70c7be8d18.

[RTann]

/retest

[daynewlee]

Looks good to me