Parse APEX manifest

Modify verify to return the APEX name and version from its manifest
protobuf.

Refactor error handling a bit, improving the messages.

Remove the separate get_payload_vbmeta_image_hash function, merging it
into verify. (It isn't used yet, but it might be.)

Improve the tests. Also remove host_supported - we don't need it (the
reason for adding it no longer applies), and the dependencies now make
it tricky.

Bug: 308759880
Test: atest MicrodroidTests
Test: atest libapexutil_rust.test
Test: composd_cmd test-compile
Change-Id: Idd38001ab28a4a0f27b42f361b18bbab0e4aad84
diff --git a/libs/apexutil/Android.bp b/libs/apexutil/Android.bp
index f9b72c4..d248d5e 100644
--- a/libs/apexutil/Android.bp
+++ b/libs/apexutil/Android.bp
@@ -9,7 +9,9 @@
     srcs: ["src/lib.rs"],
     edition: "2021",
     rustlibs: [
+        "libapex_manifest_rs",
         "liblog_rust",
+        "libprotobuf",
         "libthiserror",
         "libvbmeta_rust",
         "libzip",