[CarPowerManager] Removed executor and added CompletableFuture

This will add an ability to cancel jobs on state transitions
while CPMS is waiting for dependant modules to complete.

Test: Manual
Bug: 112905910
Change-Id: Ib635f47129109abcc7912a71b55480751720b885
(cherry picked from commit 22eac44ee64ca93161c735ac09640a5a9f66916f)
diff --git a/car-lib/api/system-current.txt b/car-lib/api/system-current.txt
index df6b85e..c4c4385 100644
--- a/car-lib/api/system-current.txt
+++ b/car-lib/api/system-current.txt
@@ -693,7 +693,7 @@
   }
 
   public static abstract interface CarPowerManager.CarPowerStateListener {
-    method public abstract void onStateChanged(int);
+    method public abstract void onStateChanged(int, java.util.concurrent.CompletableFuture<java.lang.Void>);
     field public static final int SHUTDOWN_CANCELLED = 0; // 0x0
     field public static final int SHUTDOWN_ENTER = 1; // 0x1
     field public static final int SUSPEND_ENTER = 2; // 0x2