pfSense

Fixed to be accurate when converting from us to ms

Change us to ms for gateway alarm.

Fixes #8477 looking to be more consitent changed to use ms for gateway alarm.
Thanks to Luke Hamburg for helping with this and the code idea.
Keeping it as 0.xxxms for under 1 millisecond responses.
Just to stay ms as much as possible.

Changed ms to us Fixes #8477

Update the Copyright notice for pfSense.

rc.gateway_alarm, add syslog message that shows that a alarm was raised/cleared and what the parameters were
This helps clarify why sometimes services are restarted when reading through the syslogs.

Move copyright from ESF to Netgate

Move to Apache License 2.0

Add rc.gateway_alarm script

dpinger always pass 3 parameters to alert_cmd, what can make pfSctl confuse,
This script will be called by dpinger when alarm goes on or off, then
it's going to call pfSctl