Deduplicate CVEs

[fricklerhandwerk]

In our ingested data, many CVE numbers appear multiple times since they seem to come from different sources.

As a security team member, I want to only have to deal with unique CVEs.

For example, stage the ingested data before presenting it for triage, and deduplicate it automatically as far as possible:

• Some of the data is redundant but not identical, e.g. differing only in capitalisation; pick one variant consistently
• Some data fields are filled in one variant but not the other; merge
• Some data fields conflict; present for manual resolution