Unify the configuration pattern between integrations

[selfxp]

As part of the initiative to have a similar configuration between integrations, it would be nice to use the same configuration structure as in the Datadog reporter:

additional-tags {
  service = "yes"
  host = "yes"
  instance = "yes"
  blacklisted-tags = []
}

Now if both Datadog and Prometheus are configured the service tag has to be defined multiple times as follows:

kamon {
   environemnt {
      service="serviceName"
      tags {
          service="serviceName" 
      }
   }
}