cve-check.bbclass: Add class

cve-check.bbclass: Add class

This class adds a new task for all the recipes to use
cve-check-tool in order to look for public CVEs affecting
the packages generated.

It is possible to use this class when building an image,
building a recipe, or using the "world" or "universe" cases.

In order to use this class it must be inherited and it will
add the task automatically to every recipe.

[YOCTO #7515]

Co-authored by Ross Burton & Mariano Lopez

Signed-off-by: Mariano Lopez <mariano.lopez@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>