Implements metadata

[cmizzi]

Metadatas are used in order to give more powerful data to user like counting available rows without taking care from take or skip arguments.

At now, it only implements count field. Meta are automatically generated from EloquentObjectType like :

query {
   _users_meta {
      count
   } 

   users (take: 2) {
      _posts_meta {
         count
      { 

      id
      name
      posts (take: 10) {
         id
         title
         content
      }
   }
}