Update ansible-lint configuration

Instead of excluding molecule configurations for systemd individually we
instead direct ansible-lint to process any of these configurations in
scenario directories as plain yaml files. This mirrors how ansible-lint
handles `molecule.yml` files in scenario directories by default.

.ansible-lint

@@ -13,7 +13,10 @@ exclude_paths:
   - .cache
   # Seems wise to ignore this too
   - .github
-  # These two are Molecule configuration files, not Ansible playbooks
-  - molecule/default/molecule-no-systemd.yml
-  - molecule/default/molecule-with-systemd.yml
+kinds:
+  # This will force our systemd specific molecule configurations to be treated
+  # as plain yaml files by ansible-lint. This mirrors the default kind
+  # configuration in ansible-lint for molecule configurations:
+  # yaml: "**/molecule/*/{base,molecule}.{yaml,yml}"
+  - yaml: "**/molecule/*/molecule-{no,with}-systemd.yml"
 use_default_rules: true