Cli: cleanup gpio commands (#1306)

* Cli: cleanup gpio commands

* Cli: extra gpio message for debug pins

applications/cli/cli_command_gpio.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#include "cli_i.h"
+
+void cli_command_gpio(Cli* cli, string_t args, void* context);