Threat control LWRP

Cf. first commit and README changes:

Add a threat_control LWRP, allowing to whitelist/blacklist IPs on CloudFlare
* Stores last action in a node attribute cache, CF API is only called once per day, or if status changes
* IP attribute defaults to current's node IP address
"Nothing to do" and "ignoring" (as in _"ignoring this resource in the list of things to do, it's already good"_) sound quite similar on my end − except one is shorter. :-)
Still updating for consistency: 3b36dec

`updated_by_last_action`: eb2c9d0
Shouldn't that boolean be set in the resource though, as it's where the action does occur?