This fixes https://github.com/prometheus/alertmanager/issues/881 Also add some unit tests
Turn the GroupKey into a string that is composed of the matchers if the path in the routing tree and the grouping labels. Only hash it at the very end to ensure we don't exceed size limits of integration APIs.
This commit packages up individual modules and removes the top-level main package.
Brian Brazil
Corentin Chary
Fabian Reinartz