Add new file 100-monitor_kernel_version.inc.php to stable-3.1 in relation to...

Add new file 100-monitor_kernel_version.inc.php to stable-3.1 in relation to recently merged commits of ispconfig/ispconfig3!790 and ispconfig/ispconfig3!791.

There is a fix to the filename for master submitted via commit ispconfig/ispconfig3!804 that is still pending.