cas: add CAS hal

Add CAS hal definitions and default service implementation.

bug: 22804304

Change-Id: I0a89608fe75c5f3c5e6888f9b771305742760707
diff --git a/cas/Android.bp b/cas/Android.bp
new file mode 100644
index 0000000..57532a0
--- /dev/null
+++ b/cas/Android.bp
@@ -0,0 +1,6 @@
+// This is an autogenerated file, do not edit.
+subdirs = [
+    "1.0",
+    "1.0/default",
+    "native/1.0",
+]