Intrinsic security for template engine

The intrinsic security implementation only supported predefined
topologies but did not work with devices created by the template engine.
This change address that and a bunch of other issues:
* A new genkeys.py module for key management by python scripts
* read_topology uses the new genkeys module
* xconfig autodetects source base and builds template paths based on it
* xconfig also generates a resolv.conf if device runs nameserver
* xianet allows nameserver to run on a router
* xianet can now run from any directory. It detects where xconfig.py is.
* xia_router_lib.click was missing two new args for XIALineCard in
  XIARouter4port. Added those
Merge branch 'intrinsic_security' of github.com:XIA-Project/xia-core into intrinsic_security