public static void markWriteStoragePermissionRequested(final Context context) {
        final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
        preferences.edit().putBoolean(PREFS_WRITE_STORAGE_PERMISSION_REQUESTED, true).apply();
    }
The first time an app requests a permission there is no 'Don't ask again' checkbox and
{@link ActivityCompat#shouldShowRequestPermissionRationale(Activity, String)} returns false.
This situation is similar to a permission being denied forever, so to distinguish both cases
a flag needs to be saved.

@param context the context
app/src/main/java/no/nordicsemi/android/nrfmesh/utils/Utils.java