[metrics-alerts] Retiring metrics alerts in its current format

[Silvia/Hiro]

Hi everyone,

Moving forward we are going to use this list as a service only list
where admins will be receiving information about metrics services. We
are talking about heartbeats and logs. Because we don't want to spam
subscribers with services internals we are going to unsubscribe most
people from the list.

For discussions about metrics and activities from the Network health
team you can subscribe to network-health at lists.torproject.org.


Cheers,

-hiro