Add emacsclient desktop file equivalent on Android

* doc/emacs/android.texi (Android File System):
* java/AndroidManifest.xml.in: Update with new activity.  Remove
Android 10 restrictions through a special flag.

* java/org/gnu/emacs/EmacsNative.java (getProcName): New
function.
* java/org/gnu/emacs/EmacsOpenActivity.java (EmacsOpenActivity):
New file.
* java/org/gnu/emacs/EmacsService.java (getLibraryDirection):
Remove unused annotation.
* lib-src/emacsclient.c (decode_options): Set alt_display on
Android.
* src/android.c (android_proc_name): New function.
(NATIVE_NAME): Export via JNI.

java/org/gnu/emacs/EmacsService.java

@@ -152,7 +152,6 @@ public class EmacsService extends Service
       }
   }
 
-  @TargetApi (Build.VERSION_CODES.GINGERBREAD)
   private String
   getLibraryDirectory ()
   {