Changed activity creation logic

- for home activity it will reuse existing activity from back stack and
  also clears all current activities
- for nearby, about and settings, it will use the existing activity from
  back stack

app/src/main/java/fr/free/nrw/commons/contributions/ContributionsActivity.java

@@ -343,9 +343,4 @@ public class ContributionsActivity extends AuthenticatedActivity
     public void refreshSource() {
         getSupportLoaderManager().restartLoader(0, null, this);
     }
-
-    public static void startYourself(Context context) {
-        context.startActivity(new Intent(context, ContributionsActivity.class));
-    }
-
 }