Define ANSIBLE_ROLES_PATH for the ansible provisioner

[jsf9k]

🗣 Description

This pull request modifies the molecule.yml file to define the ANSIBLE_ROLES_PATH environment variable, inserting the path to the repository checkout directory.

💭 Motivation and context

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.

Without this change molecule can no longer find the skeleton-ansible-role Ansible role.

🧪 Testing

All automated tests pass.

✅ Pre-approval checklist

• This PR has an informative and human-readable title.
• Changes are limited to a single goal - eschew scope creep!
• All relevant type-of-change labels have been added.
• I have read the CONTRIBUTING document.
• These code changes follow cisagov code standards.
• All new and existing tests pass.

[dav3r]

If it works for you, then it works for me. 👍

[mcdonnnj]

Seems like a reasonable enough solution to this problem. I have one question for your consideration.