moving non critical settings to sd

based on WillyJL's work

TODO: fix loader_menu

applications/services/bt/bt_service/bt_settings_api_i.h

@@ -3,6 +3,14 @@
 #include "bt.h"
 #include "../bt_settings.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void bt_get_settings(Bt* bt, BtSettings* settings);
 
 void bt_set_settings(Bt* bt, const BtSettings* settings);
+
+#ifdef __cplusplus
+}
+#endif