vSphere DRS Anti-Affinity VM-VM rule creation / updating via EKSCTL

**What would you like to be added**:
The ability to enable vSphere DRS Anti-Affinity VM-VM rule creation so that control plane, etcd, and worker nodes don't all end up on the same ESXi node

**Why is this needed**:
Code to be added into eksctl to interact with vCenter for the rule creation and updating, anti-affinity rules should be settable for control planes, etcd, and worker nodes

Start by locating eksctl's vCenter integration and the cluster node placement paths. Define how anti-affinity rule creation and updating should work for control planes, etcd, and worker nodes, then verify that each group can be configured without placing all nodes on one ESXi host.

Written by the indexing model from the issue text.