TUN-8728: implement diag/tunnel endpoint

## Summary
The new endpoint returns the current information to be used when calling the diagnostic procedure.
This also adds:
- add indexed connection info and method to extract active connections from connTracker
- add edge address to Event struct and conn tracker
- remove unnecessary event send
- add tunnel configuration handler
- adjust cmd and metrics to create diagnostic server

Closes TUN-8728

metrics/metrics.go

@@ -94,6 +94,7 @@ func newMetricsHandler(
 		})
 	}
 
+	router.HandleFunc("/diag/tunnel", config.DiagnosticHandler.TunnelStateHandler)
 	router.HandleFunc("/diag/system", config.DiagnosticHandler.SystemHandler)
 
 	return router