Reland "[Android WebAPK] Link to a shortcuts file from the manifest."

This is a reland of f0ecb909.

Previously, the original commit was reverted to land another CL and push
the shell apk immediately. There was nothing wrong with the original CL.
Since the other CL was landed and pushed, we can now reland this CL.

Original change's description:
> [Android WebAPK] Link to a shortcuts file from the manifest.
>
> Instructions for enabling Android shortcuts:
> https://developer.android.com/guide/topics/ui/shortcuts/creating-shortcuts
>
> This is the first step for enabling shortcuts. The server will populate
> shortcuts.xml depending on the Manifest shortcuts provided (and also
> generate additional string resource files).

> Bug: 1010471
> Change-Id: I2e0a6118a22869766e4b5e849dabc6533cd2d306
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1864805
> Reviewed-by: Peter Kotwicz <pkotwicz@chromium.org>
> Commit-Queue: Rayan Kanso <rayankans@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#707889}

Bug: 1010471
Change-Id: Idb2c09bc6d259766f79f837bf8de9a9e2278933b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1895856Reviewed-by: Peter Kotwicz <pkotwicz@chromium.org>
Commit-Queue: Henry Jian <hzjian@google.com>
Cr-Commit-Position: refs/heads/master@{#711868}

chrome/android/webapk/shell_apk/AndroidManifest.xml

@@ -59,6 +59,7 @@
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
+            <meta-data android:name="android.app.shortcuts" android:resource="@xml/shortcuts" />
         </activity>
         <activity android:name="org.chromium.webapk.shell_apk.h2o.SplashActivity"
                   android:theme="@style/SplashTheme"
@@ -76,6 +77,7 @@
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
+            <meta-data android:name="android.app.shortcuts" android:resource="@xml/shortcuts" />
         </activity>
 
         {{#share_template}}

chrome/android/webapk/shell_apk/current_version/current_version.gni

@@ -12,4 +12,4 @@
 # //chrome/android/webapk/shell_apk:webapk is changed. This includes
 # Java files, Android resource files and AndroidManifest.xml. Does not affect
 # Chrome.apk
-current_shell_apk_version = 116
+current_shell_apk_version = 117

chrome/android/webapk/shell_apk/res/xml/shortcuts.xml

+<shortcuts xmlns:android='http://schemas.android.com/apk/res/android'>
+    {{{shortcuts}}}
+</shortcuts>