Drop support for CentOS, test Rocky and Debian in CI (#92)

* Test CentOS 7 in CI

* Drop support for CentOS, test on Rocky and Debian

* Fix reset playbook for Rocky Linux

* Fix typo

* Disable firewalld during testing

Co-authored-by: Techno Tim <timothystewart6@gmail.com>

molecule/default/prepare.yml

@@ -0,0 +1,22 @@
+---
+- name: Apply overrides
+  ansible.builtin.import_playbook: >-
+    {{ lookup("ansible.builtin.env", "MOLECULE_SCENARIO_DIRECTORY") }}/overrides.yml
+
+- name: Network setup
+  hosts: all
+  tasks:
+    - name: Disable firewalld
+      when: ansible_distribution == "Rocky"
+      # Rocky Linux comes with firewalld enabled. It blocks some of the network
+      # connections needed for our k3s cluster. For our test setup, we just disable
+      # it since the VM host's firewall is still active for connections to and from
+      # the Internet.
+      # When building your own cluster, please DO NOT blindly copy this. Instead,
+      # please create a custom firewall configuration that fits your network design
+      # and security needs.
+      ansible.builtin.systemd:
+        name: firewalld
+        enabled: no
+        state: stopped
+      become: true