AP_LandingGear: add static create method

libraries/AP_LandingGear/AP_LandingGear.h

@@ -11,8 +11,14 @@
 /// @class	AP_LandingGear
 /// @brief	Class managing the control of landing gear
 class AP_LandingGear {
-
 public:
+    static AP_LandingGear create() { return AP_LandingGear{}; }
+
+    constexpr AP_LandingGear(AP_LandingGear &&other) = default;
+
+    /* Do not allow copies */
+    AP_LandingGear(const AP_LandingGear &other) = delete;
+    AP_LandingGear &operator=(const AP_LandingGear&) = delete;
 
     // Gear command modes
     enum LandingGearCommand {
@@ -28,13 +34,6 @@ public:
         LandingGear_Startup_Deploy = 2,
     };
 
-    /// Constructor
-    AP_LandingGear()
-    {
-        // setup parameter defaults
-        AP_Param::setup_object_defaults(this, var_info);
-    }
-
     /// initialise state of landing gear
     void init();
 
@@ -47,6 +46,10 @@ public:
     static const struct AP_Param::GroupInfo        var_info[];
 
 private:
+    AP_LandingGear() {
+        // setup parameter defaults
+        AP_Param::setup_object_defaults(this, var_info);
+    }
 
     // Parameters
     AP_Int16    _servo_retract_pwm;     // PWM value to move servo to when gear is retracted