Create apex containing an APK for policy delivery

This is mostly just for local prototyping, but since there are
multiple folks working on this project, this ensures that we're
all working from the same basic setup.

This changes adds an apex for sepolicy, and per-API-level APKs
(initially just API level 32) within it.

Bug: 202394777
Test: build device, verify that com.android.sepolicy.apex shows
up on device.

Change-Id: I2891f14ba5c1287b0b415adb7c88708b2359226a
diff --git a/Android.bp b/Android.bp
new file mode 100644
index 0000000..7dbf6b6
--- /dev/null
+++ b/Android.bp
@@ -0,0 +1,3 @@
+package {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}