K8S002: allow configuration for 2 replicas

[adam-rummer-hpe]

Use case

There are many applications that use leader election (e.g. controllers) to achieve redundency where there's not much practical benefit to running 3 pods over 2. This is of course different to qorum based HA where minimum 3 pods are appropriate

when running eksup, pods with 2 replicas are erroneously reported as violating K8S002 and therefore are not highly available

Solution/User Experience

some kind of configurable way to override or edit rules for specific workloads would be great, but I appreciate this means introducing a config file and that adds a lot of complication

An ideal solution would allow me to say "workload X should have minimum Y replicas" so that we don't accidentally green light a workload with a single replica

Alternative solutions

The override could also be a cli flag, but I can see this getting very large for large clusters

[bryantbiggs]

I think that makes sense - and would be applicable for other aspects such as #5