Implement Get / Get All Orders V2

[jswift]

Since it doesn't seem like Orders V3 will support retrieval of orders anytime soon, I think we need to implement it here.

https://developer.bigcommerce.com/api-reference/store-management/orders/orders/getallorders

[jswift]

Currently this would be possible with

$api = new BigCommerce\ApiV2\V2ApiClient($_ENV['hash'], $_ENV['CLIENT_ID'], $_ENV['ACCESS_TOKEN']);
$httpClient = $api->getRestClient();

$ordersResponse = $httpClient->get('/orders');