CVEs, CPEs, OVAL definitions and CERT advisories now use integer scores
from 0 to 100 instead of CVSS scores.
CVEs now also use CVSS v3 if available and store CVSS vector strings
instead of individual components.

The "severity", "cvss", "max_cvss" elements and filters are replaced
with the new score ones. Only the filter keyword "severity" is kept
for filter and aggregate / chart compatibility.

For simplicity all the new score elements and filter columns should be
named the same.

The functions were still trying to use the old "cvss" field.
Also, the doc comment of cve_cvss_base has been fixed.

The doc comments are updated to refer to the new scoring instead of
CVSS scores and -1 instead of NULL for finished iteration values.