AP_FWVersion: add structure to hold firmware version

libraries/AP_Common/AP_FWVersion.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include "ap_version.h" // header generated by build system
+
+#include <stdint.h>
+#include <GCS_MAVLink/GCS_MAVLink.h>
+
+typedef struct {
+    uint8_t major;
+    uint8_t minor;
+    uint8_t patch;
+    FIRMWARE_VERSION_TYPE fw_type;
+    const char *fw_string;
+} AP_FWVersion;