[MONIT-4168] Add extra configuration for remote writes

As part of the exercise to forward metrics to specific tenants extra remote write configurations are needed, on top we need to deploy fluentbit for metrics but we don't want to deploy the default remote write (as we already have our custom flow).

It might be possible to drop completely the "prometheus.server.remoteWrite" value and do it through the new "prometheus.server.additionalRemoteWrite" that provides more flexibility