Add option to start repeater on boot

Fix #9.

mobile/src/main/res/drawable/ic_action_autorenew.xml

@@ -0,0 +1,6 @@
+<vector android:autoMirrored="true" android:height="24dp"
+    android:viewportHeight="24.0" android:viewportWidth="24.0"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android"
+    android:tint="?attr/colorControlNormal">
+    <path android:fillColor="#FF000000" android:pathData="M12,6v3l4,-4 -4,-4v3c-4.42,0 -8,3.58 -8,8 0,1.57 0.46,3.03 1.24,4.26L6.7,14.8c-0.45,-0.83 -0.7,-1.79 -0.7,-2.8 0,-3.31 2.69,-6 6,-6zM18.76,7.74L17.3,9.2c0.44,0.84 0.7,1.79 0.7,2.8 0,3.31 -2.69,6 -6,6v-3l-4,4 4,4v-3c4.42,0 8,-3.58 8,-8 0,-1.57 -0.46,-3.03 -1.24,-4.26z"/>
+</vector>

mobile/src/main/res/values-zh-rCN/strings.xml

@@ -65,6 +65,7 @@
     <string name="settings_service_repeater_strict_summary">只允许通过 VPN 隧道的包通过，不适用于系统共享</string>
     <string name="settings_service_disable_ipv6">禁用 IPv6 共享</string>
     <string name="settings_service_disable_ipv6_summary">防止 IPv6 VPN 泄漏。</string>
+    <string name="settings_service_repeater_start_on_boot">开机自启动中继</string>
     <string name="settings_service_dns">备用 DNS 服务器[:端口]</string>
     <string name="settings_service_upstream">上游网络接口</string>
     <string name="settings_service_upstream_auto">自动检测系统 VPN</string>

mobile/src/main/res/values/strings.xml

@@ -70,6 +70,7 @@
         apply to system tethering.</string>
     <string name="settings_service_disable_ipv6">Disable IPv6 tethering</string>
     <string name="settings_service_disable_ipv6_summary">Enabling this option will prevent VPN leaks via IPv6.</string>
+    <string name="settings_service_repeater_start_on_boot">Start repeater on boot</string>
     <string name="settings_service_dns">Fallback DNS server[:port]</string>
     <string name="settings_service_upstream">Upstream network interface</string>
     <string name="settings_service_upstream_auto">Auto detect system VPN</string>

mobile/src/main/res/xml/pref_settings.xml

@@ -28,6 +28,10 @@
             android:title="@string/settings_service_dns"
             android:singleLine="true"
             android:defaultValue="8.8.8.8"/>
+        <SwitchPreference
+            android:key="service.repeater.startOnBoot"
+            android:icon="@drawable/ic_action_autorenew"
+            android:title="@string/settings_service_repeater_start_on_boot"/>
         <be.mygod.vpnhotspot.preference.AlwaysAutoCompleteEditTextPreference
             android:key="service.upstream"
             android:icon="@drawable/ic_action_settings_ethernet"