Add start of settings app for senstivity.

really just debugging. I want to make it more configurable then high med low.
Position of setting needs a new location...dynamicly adding it currently at the end. Which honestly im fine with.

src/displayapp/Apps.h

@@ -36,7 +36,9 @@ namespace Pinetime {
       SettingSteps,
       SettingSetDate,
       SettingSetTime,
-      Error,
+      SettingShakeThreshold,
+      Error
+
     };
   }
 }