DNS update on preemption

[dfernandezm]

Every time a node is preempted in GKE, there's a new one coming up. Our dev setup uses the IP of 'one' node as A record in Cloudflare. The domain stops resolving as the nodes change IPs:

TODO:

• Detect preemption in GKE - Deploy add-on to detection node termination/preemption on GKE #43
• Setup cloudflare API to change DNS record - Client to setup DNS in Cloudflare #42
• Call DNS setup with IP on preemption - Update DNS in Cloudflare on node startup #44

This way we should have a stable DNS