Move some system services to their own sub package.

As a next step they can be moved into separate directories to be
built as separate modules that may or may not be included in a
particular configuration.

Moves AppWidgetService, BackupManagerService, ClipboardService, DevicePolicyMS,
and WallpaperMS.

Change-Id: I33e48d070f38186819d3a1d7a4dc3984b75a9eda
diff --git a/services/java/com/android/server/SystemServer.java b/services/java/com/android/server/SystemServer.java
index a42cbcf..e4af687 100644
--- a/services/java/com/android/server/SystemServer.java
+++ b/services/java/com/android/server/SystemServer.java
@@ -51,7 +51,11 @@
 import com.android.server.accounts.AccountManagerService;
 import com.android.server.am.ActivityManagerService;
 import com.android.server.am.BatteryStatsService;
+import com.android.server.appwidget.AppWidgetService;
+import com.android.server.backup.BackupManagerService;
+import com.android.server.clipboard.ClipboardService;
 import com.android.server.content.ContentService;
+import com.android.server.devicepolicy.DevicePolicyManagerService;
 import com.android.server.display.DisplayManagerService;
 import com.android.server.dreams.DreamManagerService;
 import com.android.server.input.InputManagerService;
@@ -67,6 +71,7 @@
 import com.android.server.print.PrintManagerService;
 import com.android.server.search.SearchManagerService;
 import com.android.server.usb.UsbService;
+import com.android.server.wallpaper.WallpaperManagerService;
 import com.android.server.wifi.WifiService;
 import com.android.server.wm.WindowManagerService;