Add settings to disable DoH

Close #3130

app/src/main/java/com/topjohnwu/magisk/ui/settings/SettingsItems.kt

@@ -174,6 +174,15 @@ object UpdateChecker : BaseSettingsItem.Toggle() {
         }
 }
 
+object DoHToggle : BaseSettingsItem.Toggle() {
+    override val title = R.string.settings_doh_title.asTransitive()
+    override val description = R.string.settings_doh_description.asTransitive()
+    override var value = Config.doh
+        set(value) = setV(value, field, { field = it }) {
+            Config.doh = it
+        }
+}
+
 // check whether is module already installed beforehand?
 object SystemlessHosts : BaseSettingsItem.Blank() {
     override val title = R.string.settings_hosts_title.asTransitive()

app/src/main/java/com/topjohnwu/magisk/ui/settings/SettingsViewModel.kt

@@ -58,7 +58,7 @@ class SettingsViewModel(
         // Manager
         list.addAll(listOf(
             Manager,
-            UpdateChannel, UpdateChannelUrl, UpdateChecker, DownloadPath
+            UpdateChannel, UpdateChannelUrl, DoHToggle, UpdateChecker, DownloadPath
         ))
         if (Info.env.isActive) {
             list.add(ClearRepoCache)