Add a property to reflect the app debuggability

Set a build-time config to declare app debuggability that is used as
input to DICE and by apps, such as compos, that make decisions based on
this state. This will make it easier to tweak the definition of
debuggability and keep it consistent across dependents.

Bug: 219740340
Test: atest ComposHostTestCases
Test: atest MicrodroidTests
Change-Id: I770ae615a958dd6939925c400336a2550a3d950d
diff --git a/microdroid/bootconfig.app_debuggable b/microdroid/bootconfig.app_debuggable
index 5257b6e..0d85186 100644
--- a/microdroid/bootconfig.app_debuggable
+++ b/microdroid/bootconfig.app_debuggable
@@ -1,3 +1,6 @@
+# The app is debuggable.
+androidboot.microdroid.app_debuggable=1
+
 # TODO(b/203369076) This should be 0 to disable adb rooting. For now, we can't do that because
 # if this is set to 0, adbd enforces the host authentication but we don't put the adb
 # public key (which represents the owner) in the VM yet.