AAPT2: Set the minSdkVersion when generating multiple APKs.

When generating multiple APKs from a configuration file, check to see if
we have filtered resource by minSdkVersion and update the manifest to
reflect this. We only want to inflate and modify the manifest file if
there is an update to be applied.

Bug: 37944703
Bug: 67005138

Test: Ran unit tests
Test: Manually split an APK and verified the manifest by dumping with
      AAPT (both xmltree and badging).

Change-Id: I64a0e4889d7d9e57373369b044a091287b06cc35
diff --git a/tools/aapt2/configuration/ConfigurationParser.h b/tools/aapt2/configuration/ConfigurationParser.h
index 9bc9081..ebf1c98 100644
--- a/tools/aapt2/configuration/ConfigurationParser.h
+++ b/tools/aapt2/configuration/ConfigurationParser.h
@@ -103,14 +103,14 @@
 };
 
 struct AndroidSdk {
-  Maybe<std::string> min_sdk_version;
-  Maybe<std::string> target_sdk_version;
-  Maybe<std::string> max_sdk_version;
+  Maybe<int> min_sdk_version;
+  Maybe<int> target_sdk_version;
+  Maybe<int> max_sdk_version;
   Maybe<AndroidManifest> manifest;
 
-  static AndroidSdk ForMinSdk(std::string min_sdk) {
+  static AndroidSdk ForMinSdk(int min_sdk) {
     AndroidSdk sdk;
-    sdk.min_sdk_version = {std::move(min_sdk)};
+    sdk.min_sdk_version = min_sdk;
     return sdk;
   }