ENH: Heartbeat notification

[jschrempp]

Now that the code has alarms, there is a chance that we will remove the WP notifications because they are annoying. With these gone, how will the user be assured that the monitoring system is active? The user could always look at the logging spreadsheet to see that new events are being added.

The proposal is to add a weekly heartbeat notification. In that it would report: number of well pump cycles since the last heartbeat; number of pressure pump cycles since the last heartbeat; number of days the WSM has been up and running (days since last reboot). This weekly heartbeat text would be less annoying yet provide assurance that the WSM is still alive.