Checkout oauth

Backend for oauth

Sets up a redirect that refers users to /checkout with a session token

Sets up a new implicit grant in oauth. If the session token is set, it will issue a implicit grant and jwt for the logged in user

Added an api that writes sendwyre user accounts to a cassandra table that uses the user's guid as a primary key.

We'll need to set the "checkout_url" to the base hostname of the checkout site.

#261 (closed)

Controllers/checkout.php

@@ -13,7 +13,7 @@ class checkout implements Interfaces\Api
 {
     public function get($pages)
     {
-        $checkoutKey = ['checkout_key' => base64_encode(openssl_random_pseudo_bytes(8))];
+        $checkoutKey = ['checkout_key' => base64_encode(openssl_random_pseudo_bytes(8)), 'usd' => $_GET['usd'] ?? 25];
         $cookie = new Cookie();
         $cookie
             ->setName('checkout_key')