Test playbook using molecule (#67)

* Test cluster using molecule

* Fix detection of first control node

* Include --flannel-iface and --node-ip as k3s arguments

* Store logs of k3s-init.service as GitHub job artifacts

molecule/default/overrides.yml

@@ -0,0 +1,11 @@
+---
+- name: Apply overrides
+  hosts: all
+  tasks:
+    - name: Override host variables
+      ansible.builtin.set_fact:
+        # See: https://github.com/flannel-io/flannel/blob/67d603aaf45ef80f5dd39f43714fc5e6f8a637eb/Documentation/troubleshooting.md#Vagrant  # noqa yaml[line-length]
+        flannel_iface: eth1
+
+        # The test VMs might be a bit slow, so we give them more time to join the cluster:
+        retry_count: 45