HPCC-12226 Push kernel message info new section of workunit

Add a virtual to IPerfMonHook to allow kernel logs captured by
the monitor to be redirected.
Implement a hook method that fires the kernel messages to a
'Alert' section in workunit.
Default to capturing kernel message of level <=3, which means
KERN_EMERG, KERN_ALERT, KERN_CRIT, KERN_ERR

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>