Do not allow untrusted_app to open tun_device

Third party vpn apps must receive open tun fd from the framework
for device traffic.

neverallow untrusted_app open perm and auditallow bluetooth
access to see if the neverallow rule can be expanded to include
all of appdomain.

Bug: 24677682
Change-Id: I68685587228a1044fe1e0f96d4dc08c2adbebe78