Migrate DICE access to IVmPayloadService

Take control of the microdroid interface to DICE so we can eventually
expose only what we need to with a simple interface.

Merge the DICE logic into microdroid_manager, removing a process,
removing IDiceMaintenance, and replacing IDiceNode with
IVmPayloadService for access to the DICE values. The current interface
is just meant to be enough to migrate current payload but it will need
to be refined.

The new interface is exposed in the vm_payload library and clients are
updated to use the new library functions.

Bug: 243133253
Bug: 243514248
Test: atest MicrodroidTests
Test: atest ComposHostTestCases
Change-Id: I2d659576ca3ccdb8f8ffd9d22ff0d1b96e85a3b8
diff --git a/microdroid/ueventd.rc b/microdroid/ueventd.rc
index fc165c8..268d3a2 100644
--- a/microdroid/ueventd.rc
+++ b/microdroid/ueventd.rc
@@ -28,4 +28,4 @@
 # Virtual console for logcat
 /dev/hvc2                 0666   system     system
 
-/dev/open-dice0           0660   diced      diced
+/dev/open-dice0           0660   root       root