Add Enable New TUN Feature option

When enabled, TUN will use hev-socks5-tunnel; otherwise, it will use badvpn-tun2socks

V2rayNG/app/src/main/java/com/v2ray/ang/AppConfig.kt

@@ -62,6 +62,7 @@ object AppConfig {
     const val PREF_IS_BOOTED = "pref_is_booted"
     const val PREF_CHECK_UPDATE_PRE_RELEASE = "pref_check_update_pre_release"
     const val PREF_GEO_FILES_SOURCES = "pref_geo_files_sources"
+    const val PREF_USE_HEV_TUNNEL = "pref_use_hev_tunnel"
 
     /** Cache keys. */
     const val CACHE_SUBSCRIPTION_ID = "cache_subscription_id"