Feat/listening address

[paologallinaharbur]

Testing it locally with:

cluster_name: test
license_key: test2

go run ./cmd/nri-prometheus/... -config_path ./config

curl localhost:8080/metrics
# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.
# TYPE go_gc_duration_seconds summary
go_gc_duration_seconds{quantile="0"} 0.000131

Adding

cluster_name: test
license_key: test2
self_metrics_listening_address: ":8181"

We can run:

curl localhost:8181/metrics
# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.
# TYPE go_gc_duration_seconds summary
go_gc_duration_seconds{quantile="0"} 0.000131

[marcsanmi]

LGTM 🚀