Fix crash on Archive:+packages with non-Debian packages
When non-Debian-format packages are published to archives via CI builds,
they don't have a component or a section, since that only makes sense
for Debian-format packages. This caused the Archive:+packages page to
crash. Just leave the relevant cell empty in that case.
- `CVE` class is renamed to `UCTRecord`
- `UCTRecord` holds the information about a CVE, its structure
mirrors the UTC CVE files
- `UCTRecord` class is responsible for reading the UCT CVE files
- `CVE` class now holds the CVE information using LP types
(SourcePackageName, DistributionSourcePackage, BugTaskImportance, etc.)
- `CVE` class is responsible for transforming raw `UCTRecord`
to data types which are specific to LP
- `UTCImporter` is now responsible only for creating bugs,
bug tasks and vulnerabilities, all necessary data massaging
is done by the `CVE` class