[Move] Introduce Witness and authority design pattern #53

module moveos_std::type_info{

   /// Returns the module authority for the TypeInfo of type `T`
   public fun module_authority<T>(): TypeInfo {
       let TypeInfo {
            account_address,
            module_name,
            struct_name: _,
        } = type_of<T>();

        TypeInfo {
            address_,
            module_name,
            struct_name: b"Witness",
        }
   }
}

moveos_std::bcd{
   public(friend) native fun from_bytes<MoveValue>(bytes: vector<u8>): MoveValue;
}

module moveos_std::bcd{
   public(friend) native fun internal_from_bytes<MoveValue>(bytes: vector<u8>): MoveValue;
   public fun from_bytes<W,MoveValue>(witness: W, bytes: vector<u8>): MoveValue{
      assert!(type_info::module_authority<MoveValue> == type_info::type_of<W>, ENO_MODULE_AUTHORITY);
      internal_from_bytes(bytes)
   }
}

module my_app:my_module{
   struct Witness{}
   struct MyResource{}
   
   public fun new_from_bytes(bytes:&vector<u8>): MyResource{
      bcd::from_bytes<Witness, MyResource>(Witness{}, bytes) 
   }
}