do some refactor

1. Route must impl PeerPacketFilter trait.
2. Use postcard lib to serial msg instead of bincode.
3. Fix cycle ref in peer_mgr & peer_rpc

easytier-core/src/gateway/udp_proxy.rs

@@ -26,10 +26,7 @@ use tracing::Level;
 
 use crate::{
     common::{error::Error, global_ctx::ArcGlobalCtx, PeerId},
-    peers::{
-        packet,
-        peer_manager::{PeerManager, PeerPacketFilter},
-    },
+    peers::{packet, peer_manager::PeerManager, PeerPacketFilter},
     tunnels::common::setup_sokcet2,
 };