create molecule scenario and adapt role

molecule/default/converge.yml

@@ -0,0 +1,6 @@
+---
+- name: Converge
+  hosts: all
+  
+  roles:
+    - ansible-role-acme

molecule/default/molecule.yml

@@ -0,0 +1,19 @@
+---
+dependency:
+  name: galaxy
+driver:
+  name: docker
+platforms:
+  - name: buster-acme-molecule
+    image: debian:buster-slim
+    pre_build_image: true
+  - name: focal-acme-molecule
+    image: ubuntu:focal
+    pre_build_image: true
+provisioner:
+  name: ansible
+  config_options:
+    defaults:
+      interpreter_python: /usr/bin/python3
+verifier:
+  name: ansible

molecule/default/prepare.yml

@@ -0,0 +1,10 @@
+- name: Prepare
+  hosts: all
+  gather_facts: no
+
+  tasks:
+    - name: Update apt cache
+      raw: apt update
+
+    - name: Install python3 package
+      raw: apt install -y --no-install-recommends python3