adds checkoutAssetMail class, and content method

app/Notifications/CheckoutAssetNotification.php

@@ -191,35 +191,5 @@ public function toGoogleChat()
      * @param  mixed  $notifiable
      * @return \Illuminate\Notifications\Messages\MailMessage
      */
-    public function toMail()
-    {   $this->item->load('assetstatus');
-        $eula = method_exists($this->item, 'getEula') ? $this->item->getEula() : '';
-        $req_accept = method_exists($this->item, 'requireAcceptance') ? $this->item->requireAcceptance() : 0;
-        $fields = [];
 
-        // Check if the item has custom fields associated with it
-        if (($this->item->model) && ($this->item->model->fieldset)) {
-            $fields = $this->item->model->fieldset->fields;
-        }
-
-        $accept_url = is_null($this->acceptance) ? null : route('account.accept.item', $this->acceptance);
-
-        $message = (new MailMessage)->markdown('notifications.markdown.checkout-asset',
-            [
-                'item'          => $this->item,
-                'admin'         => $this->admin,
-                'status'        => $this->item->assetstatus?->name,
-                'note'          => $this->note,
-                'target'        => $this->target,
-                'fields'        => $fields,
-                'eula'          => $eula,
-                'req_accept'    => $req_accept,
-                'accept_url'    => $accept_url,
-                'last_checkout' => $this->last_checkout,
-                'expected_checkin'  => $this->expected_checkin,
-            ])
-            ->subject(trans('mail.Confirm_asset_delivery'));
-
-        return $message;
-    }
 }