Retire the #dev-ops-notifications channel

[jchristgit]

Our #dev-ops-notifications channel is not being reviewed actively, and
presumably has not been for a long time. We should remove it.

The reasoning is relatively clear. When looking into the channel, we find a
large amount of almost completely unactionable problems with absolutely no
cross-referencing or other useful information. An issue was made to improve
this situation in Olli in August 2021, but has received no traction, see
python-discord/olli#12.

To further drive the point home, over the past few days, I have added a webhook
that periodically sends defamatory statements whilst impersonating Joe, and
nobody has complained yet. I therefore ask we remove the channel.

[MarkKoz]

Let's open a discussion about what this channel was trying to achieve. Evidently it has failed, but were we trying to resolve real problems at the time? Have these problems since been solved by other means?

I am 100% on board with only showing actionable items when it comes to operational alerts. However, there is a grey area there. For example, let's say we have a hard dependency on a third party service. If that service experiences downtime, it is likely out of our control and there is nothing immediately actionable. But we still want visibility into it, so that we can assess impact and notify users downstream. And in the long term, such things can spark discussions like "Why do we have this dependency? Is there an alternative?" This is just one example from my experience that shows how it can be tricky to set the bar for alerting.