Installing `containerd` doesn't require `kubernetes` repositories to be configured

[NicolasT]

Currently when running the metalk8s.containerd state, it includes the metalk8s.repo state which configures EPEL and the kubernetes repository on the system. There's no need to include the latter to install containerd or its dependencies, so the kubernetes repository should not be configured on the system.

How this is done (by keeping the metalk8s.repo state and splitting it up, or not keeping it and moving repository management into states more locally) is TBD.