Move configuration of servers completely to ansible

With this change we no longer use user-data scripts on the provided
machines. That makes it way easier for me to handle all the
configuration, since I only have to run ansible. Furthermore this the
burdon to think what may went wrong, since ansible is easier to debug
than some arbitrary scripts which run at provisioning-time on the
machines.

With this change I should also think about restructuring the code a bit
as well. Since it's actually easier to provide the initial
software-stack for the cluster via ansible than via terraform, at least
as far as I can tell right now.

README.adoc

@@ -14,7 +14,7 @@ The setup is split into 2 dedicated parts:
 cd infra
 terraform init
 terraform apply
-sleep 300 # Wait 5 minutes to allow the user-data script to finish
+sleep 300 # Wait 5 minutes since the machines start _slow_ sometimes
 cd ../k3s
 ansible-galaxy install -r requirements.yml 
 ansible-playbook site.yml