moved actions to ready() to be able to hook into methods, made addProduc...

...tToCart hookable

As example for use of the hook. I have a hook to show a message on front-end when adding or removing item.

```
/**
     * show message when product added to cart
     */
    public function addToCartHook(HookEvent $event) {
        $qty = $event->arguments("qty");
        $product = $event->arguments("product");
        if (strpos($product->template->name, "repeater_") === 0) {
            $page = $product->getForPage(); // get page where repeater lives
            $title = $page->title . ": " . $product->title;
        } else {
            $title = $product->title;
        }
        if($qty < 1 && $event->return == true) {
            wire("session")->message("$title entfernt");
        } elseif($event->return == true) {
            wire("session")->message("$qty x <strong>$title</strong> hinzugefügt");
        }
    }
```