[sign_virt_apex] Update vbmeta related bootconfigs

Signing microdroid super images will change vbmeta digest & size, these
are embedded in ramdisk & hence need to be changed too. For this we
detach the bootconfigs from ramdisk, update them & re-attach them.

Other then that, this patch also removes signing of legacy images like
bootloader.

Test: atest
MicrodroidHostTests#testBootSucceedsWhenNonProtectedVmStartsWithImagesSignedWithDifferentKey
Bug: 245277660

Change-Id: Ia1d2ab0a7c76c7ee7435e55bab9a1c9d4f29f202
diff --git a/apex/Android.bp b/apex/Android.bp
index dce8edd..64836ff 100644
--- a/apex/Android.bp
+++ b/apex/Android.bp
@@ -146,7 +146,10 @@
         },
     },
     required: [
+        // sign_virt_apex should be runnable from outside the source tree,
+        // therefore, any required tool should be listed in build/make/core/Makefile as well.
         "img2simg",
+        "initrd_bootconfig",
         "lpmake",
         "lpunpack",
         "simg2img",
@@ -167,6 +170,7 @@
         // sign_virt_apex
         "avbtool",
         "img2simg",
+        "initrd_bootconfig",
         "lpmake",
         "lpunpack",
         "sign_virt_apex",