linux/generate-cve-exclusions: use data from CVEProject

linux/generate-cve-exclusions: use data from CVEProject

The old script was relying on linuxkernelcves.com that was archived in
May 2024 when kernel.org became a CNA.

The new script reads CVE json files from the datadir that can be either
from the official kernel.org CNA [1] or CVEProject [2]

[1] https://git.kernel.org/pub/scm/linux/security/vulns.git
[2] https://github.com/CVEProject/cvelistV5

Signed-off-by: Daniel Turull <daniel.turull@ericsson.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>