Add Guidance for Collaboration

[david-sanabria]

Why

As a data analyst (potential contributor to the playbook), I would like to be able to suggest changes and improvements in the CHHS Data Playbook so I can help improve Agency data capabilities.

How

1. Add information to the Github CONTRIB file
2. Create a site page to provide instructions for contribution
3. Add wiki pages with contributor and maintainer guidance
4. Create a template for GitHub issues to allow people to submit feedback in the form of a GitHub Issue

Acceptance Criteria

1. A data analyst can modify an existing page, and submit the changes as a pull request, given they already have a GitHub ID and access to the CHHS Data Playbook contributor instructions