Add microdroid specific sepolicy

Microdroid will have a separate sepolicy, apart from the core policy.
This is the first step; For now it's a simple copy of system/sepolicy.
For the future work, it will be stripped.

Bug: 189165759
Test: boot microdroid and see selinux enforced
Change-Id: I2fee39f7231560b49c93bd5e8d0feeffada40938
diff --git a/microdroid/sepolicy/system/private/mediaswcodec.te b/microdroid/sepolicy/system/private/mediaswcodec.te
new file mode 100644
index 0000000..02079c1
--- /dev/null
+++ b/microdroid/sepolicy/system/private/mediaswcodec.te
@@ -0,0 +1,6 @@
+typeattribute mediaswcodec coredomain;
+
+init_daemon_domain(mediaswcodec)
+
+get_prop(mediaswcodec, device_config_media_native_prop)
+get_prop(mediaswcodec, device_config_swcodec_native_prop)