Schwabe/lua set curve (#4955)

* Implement setCurve for lua

* Bug fixes after actual testing of API

* Fix documentation

* Even more error checking

* Add example code how to use this function

* Silence gcc warnings

* Drop points and start array index at 1 and note about wrong index in getCurve

* Add standard example

* Fixes

* Don’t use an invalid number in example

* fix missing 0

radio/src/datastructs.h

@@ -367,7 +367,7 @@ PACK(struct FlightModeData {
 PACK(struct CurveData {
   uint8_t type:1;
   uint8_t smooth:1;
-  int8_t  points:6; // TODO conversion
+  int8_t  points:6; // TODO conversion (?!)  (describes number of points - 5)
   NOBACKUP(char name[LEN_CURVE_NAME]);
 });
 #else