message: add get_owner() msg to DNS contract
diff: @@ -156,6 +156,12 @@ mod dns {
  self.get_address_or_default(name)
  }
  + /// Get owner of specific name.
  + #[ink(message)]
  + pub fn get_owner(&self, name: Hash) -> AccountId {
  + self.get_owner_or_default(name)
  + }
  +
  /// Returns the owner given the hash or the default address.
  fn get_owner_or_default(&self, name: Hash) -> AccountId {
  self.name_to_owner
  