Implement item use (energy potions)

- Selectors don't work yet

src/main/java/emu/nebula/server/handlers/HandlerItemUseReq.java

@@ -0,0 +1,35 @@
+package emu.nebula.server.handlers;
+
+import emu.nebula.net.NetHandler;
+import emu.nebula.net.NetMsgId;
+import emu.nebula.proto.ItemUse.ItemUseReq;
+import emu.nebula.net.HandlerId;
+import emu.nebula.game.player.PlayerChangeInfo;
+import emu.nebula.net.GameSession;
+
+@HandlerId(NetMsgId.item_use_req)
+public class HandlerItemUseReq extends NetHandler {
+
+    @Override
+    public byte[] handle(GameSession session, byte[] message) throws Exception {
+        // Parse request
+        var req = ItemUseReq.parseFrom(message);
+        
+        // Sanity check
+        if (req.getUse() == null) {
+            return session.encodeMsg(NetMsgId.item_use_failed_ack);
+        }
+        
+        // Create change info
+        var change = new PlayerChangeInfo();
+        
+        // Use item
+        for (var param : req.getUse().getList()) {
+            session.getPlayer().getInventory().useItem(param.getTid(), param.getQty(), change);
+        }
+        
+        // Encode and send
+        return session.encodeMsg(NetMsgId.item_use_succeed_ack, change.toProto());
+    }
+
+}