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
Nah that's a new version. Anything that alters/adds features should be a new version, so that people know right away if there's anything different/new between their cookbook and the latest version.