Define ANSIBLE_ROLES_PATH for the ansible provisioner

Molecule used to modify the roles path for us, but as of v25.2.0 no
longer does.  (See ansible/molecule#4380 for details.)  As a result we
must now modify it ourselves.

Author: jsf9k

molecule/default/molecule.yml

@@ -220,6 +220,10 @@ platforms:
     privileged: true
     volumes:
       - /sys/fs/cgroup:/sys/fs/cgroup:rw
+provisioner:
+  name: ansible
+  env:
+    ANSIBLE_ROLES_PATH: ~/.cache/molecule/skeleton-ansible-role/${MOLECULE_SCENARIO_NAME}/roles:${MOLECULE_PROJECT_DIRECTORY}/..:~/.ansible/roles:/usr/share/ansible/roles:/etc/ansible/roles
 scenario:
   name: default
 verifier: