title: Firebase Rules for Cloud Firestore to limit maximum number of documents
body: <p>I have following use case..
  I don't want to allow user control document limit in cloud firestore, I want to have firebase rule restrict it.</p>
  
  <p>For eg. I have a products collection, user can do pagination (max=10) per page. if its browser side, user can easily change and get all the products list. Is there any settings or rules to control this?</p>