Normalize all calls to make a URL into one function

[aguywithanidea]

We have separate calls everywhere that all do basically the same thing:

$form_post_url = sprintf('%s/wp-admin/admin.php?page=%s',get_bloginfo('wpurl'),$this->slug);

or ...

  private function form_action() {
    $action = sprintf('admin.php?page=%s',$this->slug);
    return $action;
  }

    $link_url = sprintf('%s&action=create_form_page',$this->form_action());
    if(function_exists('wp_nonce_url')){
      $link_url = wp_nonce_url($link_url,'create_form');
    }

or ...

$hp_base->get_form_post_url_for_page($this->slug);

This should be a common function

[aguywithanidea]

Solve needs to ensure nonced_url() can handle the cases that get_form_url_for_page() function has been handline. The former always creates absolute URLs, while the latter creates relative URLs. Need to resolve this difference as well.

Then all explicit calls should be updated to use nounced_url()

[aguywithanidea]

Patched by 94f92bb