DO NOT MERGE Fake 29.0 sepolicy prebuilts

I took current AOSP policy as base, then removed sepolicy so that the
set of type and attributes was a subset of types and attributes in Q
sepolicy, with exception of those that have not yet been cleand up in
current AOSP:

mediaswcodec_server
netd_socket
mediaextractor_update_service
thermalserviced
thermalserviced_exec

Bug: 133196056
Test: n/a
Change-Id: I2cbe749777684146114c89e1e6fc3f07400c0ae5
diff --git a/prebuilts/api/29.0/public/system_app.te b/prebuilts/api/29.0/public/system_app.te
new file mode 100644
index 0000000..023058e
--- /dev/null
+++ b/prebuilts/api/29.0/public/system_app.te
@@ -0,0 +1,7 @@
+###
+### Apps that run with the system UID, e.g. com.android.system.ui,
+### com.android.settings.  These are not as privileged as the system
+### server.
+###
+
+type system_app, domain;