A system test to exercise the rpc stop command (nanocurrency#4573)

Introduce a systest case for rpc stop command

nano/rpc/rpc.cpp

@@ -50,6 +50,7 @@ void nano::rpc::start ()
 		logger.critical (nano::log::type::rpc, "Error while binding for RPC on port: {} ({})", endpoint.port (), ec.message ());
 		throw std::runtime_error (ec.message ());
 	}
+	logger.info (nano::log::type::rpc, "RPC listening address: {}", fmt::streamed (acceptor.local_endpoint ()));
 	acceptor.listen ();
 	accept ();
 }

systest/rpc_stop.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+set -eux
+
+DATADIR=$(mktemp -d)
+
+# Start the node in daemon mode in the background
+$NANO_NODE_EXE --daemon --network dev --data_path $DATADIR --config rpc.enable=true --rpcconfig enable_control=true &
+NODE_PID=$!
+
+# Allow some time for the node to start up completely
+sleep 10
+
+# Send the stop rpc command
+curl -g -d '{ "action": "stop" }' '[::1]:45000'
+
+# Check if the process has stopped using a timeout to avoid infinite waiting
+if wait $NODE_PID; then
+    echo "Node stopped successfully"
+else
+    echo "Node did not stop as expected"
+    exit 1
+fi