guest: trusty: enable pvmfw-verified pVM for security and test VMs

- rules that use unsigned images for x86, signed images for arm64

- system_ext artifacts enabled only on devices enabling
  `trusty_system_vm` via a soong config variable:

- VM payload configuration:
  support a `placeholder_trusted_hal` soong bool variable allowing
  to enable placeholder hals on devices that don't support
  the Trusted HALs (Cuttlefish on x86_64 for example)
   (placeholder_trusted_hal shall not be enabled in production)

- security_vm: update launcher build rules to also support arm64
  and define .rc prebuilts to be reused by any device
  (not just cuttlefish)

- test_vm: enable pvmfw-verified pVM by adding image signing rules

Bug: 391719387
Bug: 391210895
Test: qemu_trusty_arm64-trunk_staging-userdebug
Change-Id: I82dc911e482538e3f22dde6246a64e712bd0f1d0
diff --git a/guest/pvmfw/avb/Android.bp b/guest/pvmfw/avb/Android.bp
index 0294322..141c1d2 100644
--- a/guest/pvmfw/avb/Android.bp
+++ b/guest/pvmfw/avb/Android.bp
@@ -33,7 +33,7 @@
         ":microdroid_kernel_signed",
         ":microdroid_initrd_normal",
         ":microdroid_initrd_debuggable",
-        ":trusty_security_vm_signed",
+        ":trusty_test_vm_signed_bin",
         ":test_image_with_one_hashdesc",
         ":test_image_with_non_initrd_hashdesc",
         ":test_image_with_initrd_and_non_initrd_desc",