support/scripts/pkg-stats: add CPE searching links

support/scripts/pkg-stats: add CPE searching links

For cases of a CPE having a unknown version or when there hasn't
been a CPE verified, proposed a search criteria to help the
user research an update.

(libcurl has NIST dict entries but not this version)
  cpe:2.3:a:haxx:libcurl:7.76.1:*:*:*:*:*:*:*
  CPE identifier unknown in CPE database (Search)

(jitterentropy-library package doesn't have any NIST dict entries)
  no verified CPE identifier (Search)

Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
[yann.morin.1998@free.fr: fix flake8 issues]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>