cve_lookup: added support for CVSS metrics v4.0+

[jstucke]

• fixed a KeyError in the CVE data parsing
• added generic support for more versions of CVSS metrics than v2, v3.0 and v3.1 (as long as the general structure of the data does not change)
  • changed the schema of the internal DB so that all scores are stored as JSON instead of storing v2 and v3.x separately
    • these changes require rebuilding the database by rerunning the installation for existing FACT installations!
  • adjusted jinja filters and the template