Support CompOS Key Service in a VM

Add the ability to start the service in a VM, and to then communicate
with it from the host via RPC Binder. Update command-line syntax.

Also revert my recent client naming change, since one tool that can
handle both host & VM seems better than two different ones.

Bug: 193603140
Test: Manual: start service in VM, connect to it, generate & verify keys.
Change-Id: I3cdb25395537e29bbfaa957eeac0c16ba4de93de
diff --git a/compos/apex/Android.bp b/compos/apex/Android.bp
index c4ab321..7638c41 100644
--- a/compos/apex/Android.bp
+++ b/compos/apex/Android.bp
@@ -38,7 +38,7 @@
 
     binaries: [
         "compos_key_cmd",
-        "compos_key_host",
+        "compos_key_main",
         "compsvc",
         "compsvc_worker",
         "pvm_exec",