commander: reboot/shutdown usability fixes

- always check with state machine before reboot/shutdown
 - respect BOARD_HAS_POWER_CONTROL (shutdown from command, low battery, power button)
 - px4_shutdown_request add optional delay and always execute from HPWORK
 - px4_shutdown_request split out px4_reboot_request

src/systemcmds/shutdown/CMakeLists.txt

@@ -33,7 +33,6 @@
 px4_add_module(
 	MODULE systemcmds__shutdown
 	MAIN shutdown
-	COMPILE_FLAGS
 	SRCS
-		shutdown.c
+		shutdown.cpp
 	)

src/systemcmds/shutdown/shutdown.cpp

@@ -1,6 +1,6 @@
 /****************************************************************************
  *
- *   Copyright (C) 2016 PX4 Development Team. All rights reserved.
+ *   Copyright (C) 2016-2020 PX4 Development Team. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -35,16 +35,10 @@
  * @file shutdown.c
  * Tool similar to UNIX shutdown command.
  */
-
+#include <px4_platform_common/shutdown.h>
 #include <px4_platform_common/tasks.h>
 
-__EXPORT int shutdown_main(int argc, char *argv[]);
-
-int shutdown_main(int argc, char *argv[])
+extern "C" __EXPORT int shutdown_main(int argc, char *argv[])
 {
-	(void)argc;
-	(void)argv;
-
-	const bool to_bootloader = false;
-	px4_systemreset(to_bootloader);
+	return px4_shutdown_request();
 }