Prevent requests to atomist network infrastructure

[kipz]

Ideas include:

• whitelisting (ips and names)
• blacklisting (ips and names)
• using a proxy service (which has actual network isolation)

[kipz]

Being able to call internal services (e.g. k8) with Rug Functions is highly desirable for us, so we need some solid way to differentiate our workloads from our customers.