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/AboutActivity.java

@@ -27,9 +27,4 @@ public class AboutActivity extends NavigationBaseActivity {
         versionText.setText(BuildConfig.VERSION_NAME);
         initDrawer();
     }
-
-    public static void startYourself(Context context) {
-        Intent settingsIntent = new Intent(context, AboutActivity.class);
-        context.startActivity(settingsIntent);
-    }
 }