Simplify molecule tests

"Upgrade" path includes multiple paths anyway:
- installing the latest official release package
- builing the current PR from source
- upgrading between the two versions

ansible/molecule/default/converge.yml

@@ -0,0 +1,10 @@
+---
+- name: update previous release to newest release
+  hosts: all
+  tasks:
+    - name: set github ref as version when available
+      set_fact:
+        paperlessng_version: "{{ lookup('env', 'GITHUB_REF') | default('latest', True) }}"
+    - name: update to newest paperless-ng release
+      include_role:
+        name: ansible