AP_Scripting: add support for controlling onvif camera using lua script

libraries/AP_Scripting/AP_Scripting.cpp

@@ -43,6 +43,10 @@
 static_assert(SCRIPTING_STACK_SIZE >= SCRIPTING_STACK_MIN_SIZE, "Scripting requires a larger minimum stack size");
 static_assert(SCRIPTING_STACK_SIZE <= SCRIPTING_STACK_MAX_SIZE, "Scripting requires a smaller stack size");
 
+#ifndef SCRIPTING_ENABLE_DEFAULT
+#define SCRIPTING_ENABLE_DEFAULT 0
+#endif
+
 extern const AP_HAL::HAL& hal;
 
 const AP_Param::GroupInfo AP_Scripting::var_info[] = {
@@ -52,7 +56,7 @@ const AP_Param::GroupInfo AP_Scripting::var_info[] = {
     // @Values: 0:None,1:Lua Scripts
     // @RebootRequired: True
     // @User: Advanced
-    AP_GROUPINFO_FLAGS("ENABLE", 1, AP_Scripting, _enable, 0, AP_PARAM_FLAG_ENABLE),
+    AP_GROUPINFO_FLAGS("ENABLE", 1, AP_Scripting, _enable, SCRIPTING_ENABLE_DEFAULT, AP_PARAM_FLAG_ENABLE),
 
     // @Param: VM_I_COUNT
     // @DisplayName: Scripting Virtual Machine Instruction Count