fix(controller): remove /run/deis/determine_registry

This script is backwards-incompatible with existing clusters. Moving the
calls to etcd directly into the unit file removes the dependency and
ultimately makes master backwards-compatible again.
Merge pull request #1512 from deis/remove-determine-registry

fix(controller): remove /run/deis/determine_registry
feat(controller): add endpoint and infrastructure for limiting memory/cpu
feat(client): add commands for managing memory/cpu limits