add exceptions, fix auth, implement response, sanitize recipient and sender

src/RecipientsList/RecipientsListInterface.php

@@ -21,9 +21,9 @@ use D3\LinkmobilityClient\ValueObject\Recipient;
 
 interface RecipientsListInterface
 {
-    public function add(Recipient $recipient);
+    public function add(Recipient $recipient) : RecipientsListInterface;
 
-    public function clearRecipents();
+    public function clearRecipents() : RecipientsListInterface;
 
     public function getRecipients() : array;
 }