feat: Add redirect to self if/when url is null
feat: Add redirect to self if/when url is null

WHY         : Because it is better to define a value instead of static
            value. It is easier to refactor
BEFORE      : When your are at the url http://example.com/abc/123
            RoutingHelper::Redirect('abc/123');
AFTER       : When your are at the url http://example.com/abc/123
            RoutingHelper::Redirect();
ALTERNATIVE : Describe another function for self redirect
NOTE        : The value must be null not empty string('')("") or
            zero (0)

erdtsksn/kadidphp,erdtsksn/kadidphp