Add ingress nightmare exploit detection signature

There is a new signature capable of detecting attempts to exploit the
ingress nightmare vulnerability (CVE-2025-1974). It works by hooking the
`security_inode_follow_link` hook and validates is a `nginx` process is
trying to resolve any `FD`s in `/proc/<pid>/fd/`.

The signature is far from perfect, as it is pretty specific to the
ingress nightmare case, but it works reliable, as the ingress process
should not resolve `FD` symlinks.

Author: patrickpichler