Start to create WS client for cli_player

rust/sea_battle_backend/src/game.rs

@@ -14,6 +14,8 @@ pub trait Player {
 
     fn is_bot(&self) -> bool;
 
+    fn opponent_connected(&self);
+
     fn set_other_player_name(&self, name: &str);
 
     fn query_boats_layout(&self, rules: &GameRules);
@@ -240,6 +242,9 @@ where
         self.players.push(msg.0);
 
         if self.players.len() == 2 {
+            self.players[0].opponent_connected();
+            self.players[1].opponent_connected();
+
             self.query_boats_disposition();
         }
     }