AP_L1_Control: add static create method

libraries/AP_L1_Control/AP_L1_Control.h

@@ -21,13 +21,16 @@
 
 class AP_L1_Control : public AP_Navigation {
 public:
-    AP_L1_Control(AP_AHRS &ahrs, const AP_SpdHgtControl * spdHgtControl)
-        : _ahrs(ahrs),
-          _spdHgtControl(spdHgtControl)
-    {
-        AP_Param::setup_object_defaults(this, var_info);
+    static AP_L1_Control create(AP_AHRS &ahrs, const AP_SpdHgtControl *spdHgtControl) {
+        return AP_L1_Control{ahrs, spdHgtControl};
     }
 
+    constexpr AP_L1_Control(AP_L1_Control &&other) = default;
+
+    /* Do not allow copies */
+    AP_L1_Control(const AP_L1_Control &other) = delete;
+    AP_L1_Control &operator=(const AP_L1_Control&) = delete;
+
     /* see AP_Navigation.h for the definitions and units of these
      * functions */
     int32_t nav_roll_cd(void) const;
@@ -72,6 +75,13 @@ public:
     }
 
 private:
+    AP_L1_Control(AP_AHRS &ahrs, const AP_SpdHgtControl *spdHgtControl)
+        : _ahrs(ahrs)
+        , _spdHgtControl(spdHgtControl)
+    {
+        AP_Param::setup_object_defaults(this, var_info);
+    }
+
     // reference to the AHRS object
     AP_AHRS &_ahrs;