Move setup of foundational service from k8s to k3s

It simply doesn't make sense to split the installation of the
kubernetes-cluster from the provisioning of foundational services.
Therefore I drop the idea to organise these services in another
terraform-setup and instead ensure their presence with ansible, as it's
already responsible for setting up the cluster and keep it up-to.date.

k3s/roles/k8s-setup/defaults/main.yml

@@ -0,0 +1,3 @@
+cert_manager_state: present
+cert_manager_version: v1.18.2
+letsencrypt_clusterissuers: {}