Add PrepareUpdateService.

It's moved from PrepareStreamingService intent service.
Now PrepareUpdateService takes an UpdateConfig and
builds PayloadSpec for UpdateEngine for both streaming
and non-streaming update.

It allows us to do all preparations in intent service's
thread, without blocking UI.

We will also add checksum verification to
PrepareUpdateService.

Test: device, junit
Bug: 77150191
Change-Id: Iea69acd9aa41e17538c26aff60f7598093ca7744
diff --git a/updater_sample/AndroidManifest.xml b/updater_sample/AndroidManifest.xml
index 18d8425..0a25116 100644
--- a/updater_sample/AndroidManifest.xml
+++ b/updater_sample/AndroidManifest.xml
@@ -33,7 +33,7 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
-        <service android:name=".services.PrepareStreamingService"/>
+        <service android:name=".services.PrepareUpdateService"/>
     </application>
 
 </manifest>