Setup Microsoft Teams notification endpoint for our Operations channel

[einari]

child of #71

I see there is a Pull Request in Grafana for this:
grafana/grafana#8533

But worst case scenario; just use the WebHook

http://docs.grafana.org/alerting/notifications/#webhook

Similar to how we've done it with AppVeyor, described at the bottom here:
https://github.com/dolittle/dotnet.build

Also documented here:
https://docs.microsoft.com/en-us/microsoftteams/platform/concepts/connectors#next-steps