update and create bundle config pb python library

update config.pb file to the source of truth:
google3/third_party/java_src/android_appbundle/bundletool/schemas/proto/config.proto

current config.pb is stale and needs update.

Also, add a python library host soong module config_proto, so that it
can be used by other python code.

BUG: b/240288941
TETS: tested along with primary_train_build_worker that reuse
BundleConfig.pb

Change-Id: I426a5cb7ec42573ed2110494c50813abc0a96296

cmd/extract_apks/bundle_proto/Android.bp

@@ -0,0 +1,13 @@
+package {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+python_library_host {
+    name: "config_proto",
+    srcs: [
+        "config.proto",
+    ],
+    proto: {
+        canonical_path_from_root: false,
+    },
+}