Put authsecret example in VAPEX

authsecret example instance is put in APEX.

Bug: 296522705
Test: authsecret HAL starts from APEX in cuttlefish/goldfish
Change-Id: I226fd57fb1ec5c8da98c07292431df055e6078d7
diff --git a/authsecret/aidl/default/manifest.json b/authsecret/aidl/default/manifest.json
new file mode 100644
index 0000000..ad5a45b
--- /dev/null
+++ b/authsecret/aidl/default/manifest.json
@@ -0,0 +1,4 @@
+{
+    "name": "com.android.hardware.authsecret",
+    "version": 1
+}