feat: unify bootstrap resources into K0sConfig

[apedriza]

Changes

• Remove in v1beta2 usage of K0sControllerConfig and K0sWorkerConfig and unify them into K0sConfig. This makes things easier in terms of UX. Now, the user will use the same resource type to declare controller or worker configs, no extra fields needed for it.
• Rename field k0s where the user defines the k0s configuration file to clusterConfig, this way is more verbose the value of the field. For example, K0sControllerConfig.spec.k0s -> K0sConfig.spec.clusterconfig
• Removed conversion. Since there is no new version of the existing resources, but replacing them, the "conversion" for backward compatibility is done in the controller by mimicking the resources in the controller logic

Fix

• Add conversion webhook in K0sControlplaneTemplate CRD

[makhov]

As I said before, it's not that easy.

clusterConfig and tunneling fields are only meaningful for controller nodes. Also args means k0s controller flags in one context and k0s worker flags in another.

And we already have K0sConfigSpec which supposed to keep common fields from both objects, we just don't use it in K0sWorkerConfig for some reason.

Also, I'm not sure that creating v1beta1 shadow objects is a good idea in general. Sounds fragile.