misc: life_mngr: refine script to trigger system shutdown request

Provide a script to user to trigger system shutdown request
in service VM or user VM.
System shutdown logic have been integrated in the lifecycle
manager, only need to send system shutdown request command
through unix domain socket in this script.

v3-->v4:
	Rewirte system shutdown trigger script using python
	since phython script have better portability.
v4-->v5:
	Update command name and copyright header.

Tracked-On: #6652

Signed-off-by: Xiangyang Wu <xiangyang.wu@intel.com>
Reviewed-by: fei1.li@intel.com

misc/services/life_mngr/s5_trigger_linux.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2021 Intel Corporation.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+import socket
+
+class SocketClient:
+    def __init__(self):
+        pass
+    def connect_to_server(self):
+        SOKET_ADDR = '/var/lib/life_mngr/monitor.sock'
+        SHUTDOWN_REQ = 'req_sys_shutdown'
+        BUF_LEN = 1024
+
+        # unix domain sockets
+        server_address = SOKET_ADDR
+        socket_family = socket.AF_UNIX
+        socket_type = socket.SOCK_STREAM
+
+        sock = socket.socket(socket_family, socket_type)
+        sock.connect(server_address)
+        sock.sendall(SHUTDOWN_REQ.encode())
+        data = sock.recv(BUF_LEN)
+        print(f"Waiting for ACK message...: {data.decode()}")
+        sock.close()
+
+if __name__ == "__main__":
+       socket_client_obj = SocketClient()
+       socket_client_obj.connect_to_server()