feat(CommentPingTeam): make the list of teams a configuration option

Instead of hard-coding them in the Service source code.

An alternative implementation would have been to make the PingTeams option some kind of global, in case in the future there are more Services that use teams. However, that would have meant passing the global configuration all the way from server.go to the specificied service, which breaks the current implementation logic, that each service only gets the small part of the config it cares about.

Any thoughts about this?

Fixes #26 (closed)