add auto update subscriptions with interval

V2rayNG/app/src/main/kotlin/com/v2ray/ang/dto/SubscriptionItem.kt

@@ -1,8 +1,11 @@
 package com.v2ray.ang.dto
 
 data class SubscriptionItem(
-        var remarks: String = "",
-        var url: String = "",
-        var enabled: Boolean = true,
-        val addedTime: Long = System.currentTimeMillis()) {
-}
+    var remarks: String = "",
+    var url: String = "",
+    var enabled: Boolean = true,
+    val addedTime: Long = System.currentTimeMillis(),
+    var lastUpdated: Long = -1,
+    var autoUpdate: Boolean = false,
+    val updateInterval: Int? = null,
+)