Add security advisories affecting 14.3R, 14.4R, 15.0R and 15.1R

FreeBSD-SA-26:37.vm affects all supported releases
FreeBSD-SA-26:38.jail affects 15.0R and 15.1R
FreeBSD-SA-26:39.execve affects all supported releases
FreeBSD-SA-26:40.zfs affects all supported releases
FreeBSD-SA-26:41.libalias affects all supported releases
FreeBSD-SA-26:42.unlinkat affects all supported releases
FreeBSD-SA-26:43.tcp affects all supported releases
FreeBSD-SA-26:44.posixshm affects all supported releases
FreeBSD-SA-26:45.audit affects all supported releases
FreeBSD-SA-26:46.ktls affects all supported releases
FreeBSD-SA-26:47.linux affects 14.3R, 14.4R and 15.0R
FreeBSD-SA-26:48.compat32 affects 14.3R, 14.4R and 15.0R
FreeBSD-SA-26:49.iconv affects all supported releases