Reland "apex: use the same key for all microdroid items"

This reverts commit aea73f82a095871ac5537ef162ed716842169cff.

Relanding with the fix for arm & x86 builds.

apex: use the same key for all microdroid items

The pubkey embedded in bootloader should match with the key signing
VBmeta. The updated build graph is to ensure bootloader and VBmeta to be
generated with the same key.

All other filesystem images are signed with the same key for
convenience even though it's not necessary.

Bug: 193504286
Bug: 203726593
Test: atest MicrodroidHostTestCases
Change-Id: Iae93934b18955e86ee6b73ad204c68a3f7456102
diff --git a/apex/Android.bp b/apex/Android.bp
index 9d4cfdf..88487e4 100644
--- a/apex/Android.bp
+++ b/apex/Android.bp
@@ -109,3 +109,20 @@
         "simg2img",
     ],
 }
+
+// custom tool to replace bytes in a file
+python_binary_host {
+    name: "replace_bytes",
+    srcs: [
+        "replace_bytes.py",
+    ],
+    version: {
+        py2: {
+            enabled: false,
+        },
+        py3: {
+            enabled: true,
+            embedded_launcher: true,
+        },
+    },
+}