support/script/pkg-stats: show CPE ID in results

This commit improves the pkg-stats script to show the CPE ID of
packages, if available. For now, it doesn't use CPE IDs to match CVEs.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>