MEDIUM: mworker/systemd: send STATUS over sd_notify

MEDIUM: mworker/systemd: send STATUS over sd_notify

The sd_notify API is not able to change the "Active:" line in "systemcl
status". However a message can still be displayed on a "Status: " line,
even if the service is still green and "active (running)".

When startup succeed the Status will be set to "Ready.", upon a reload
it will be set to "Reloading Configuration." If the configuration
succeed "Ready." again. However if the reload failed, it will be set to
"Reload failed!".

Keep in mind that the "Active:" line won't change upon a reload failure,
and will still be green.