AP_Scheduler: add static create method

libraries/AP_Scheduler/AP_Scheduler.h

@@ -51,8 +51,13 @@
 class AP_Scheduler
 {
 public:
-    // constructor
-    AP_Scheduler(void);
+    static AP_Scheduler create() { return AP_Scheduler{}; }
+
+    constexpr AP_Scheduler(AP_Scheduler &&other) = default;
+
+    /* Do not allow copies */
+    AP_Scheduler(const AP_Scheduler &other) = delete;
+    AP_Scheduler &operator=(const AP_Scheduler&) = delete;
 
     FUNCTOR_TYPEDEF(task_fn_t, void);
 
@@ -100,6 +105,8 @@ public:
     static int8_t current_task;
 
 private:
+    AP_Scheduler();
+
     // used to enable scheduler debugging
     AP_Int8 _debug;