refactor: Move vision implementation to a new package

transport/vless/xtls.go

@@ -2,17 +2,12 @@ package vless
 
 import (
 	"context"
-	"errors"
 	"net"
 
 	tlsC "github.com/Dreamacro/clash/component/tls"
 	xtls "github.com/xtls/go"
 )
 
-var (
-	ErrNotTLS13 = errors.New("XTLS Vision based on TLS 1.3 outer connection")
-)
-
 type XTLSConfig struct {
 	Host           string
 	SkipCertVerify bool