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/dhcp.te b/microdroid/sepolicy/system/private/dhcp.te
new file mode 100644
index 0000000..8ec9111
--- /dev/null
+++ b/microdroid/sepolicy/system/private/dhcp.te
@@ -0,0 +1,7 @@
+typeattribute dhcp coredomain;
+
+init_daemon_domain(dhcp)
+type_transition dhcp system_data_file:{ dir file } dhcp_data_file;
+
+set_prop(dhcp, dhcp_prop)
+set_prop(dhcp, pan_result_prop)