Replace aapt support with aapt2

Use aapt2 instead of aapt to compile Android app resources.
Also generate all files into srcjars instead of individual
sources.

Test: m checkbuild
Change-Id: I5a67991a0daf0017e8159b46fcff7d5564a91468
diff --git a/Android.bp b/Android.bp
index 886d63d..4dddb28 100644
--- a/Android.bp
+++ b/Android.bp
@@ -209,6 +209,7 @@
         "soong-java-config",
     ],
     srcs: [
+        "java/aapt2.go",
         "java/androidmk.go",
         "java/app_builder.go",
         "java/app.go",