Remove "local" and "remote" as labels from HTTP bridge metrics

[ppatierno]

Because of the way most of the HTTP client works, every time an action is taken against the bridge, a new connection is open. It happens, for example, for the readiness and liveness probes in Kubernetes but anyway can happen with any client (while others could leave the connection opened). Currently, there are "local" and "remote" labels on each HTTP server metrics which specify the local and remote address and port for that request. The "local" is always the same while "remote" is different for each connection (at least it differs in the port part if the remote address is the same). This increases a lot the generated time series without any useful gain. We should remove these labels from HTTP related metrics.