cve-report.bbclass: add class

cve-report.bbclass: add class

Implements "report_cve" and "report_patched" tasks.

"report_patched" prepares image manifest with patched CVE info.
"report_cve" runs cvert-* scripts to generate kernel and package CVE reports.

You can configure it to set report filenames, reuse NVD feeds,
stop after manifest generation and ignore specific classes,
like native, nativesdk, etc.

Signed-off-by: grygorii tertychnyi <gtertych@cisco.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>