Update/oss details

[jeffpaul]

Description of the Change

This PR adds the GPLv2 license file and associated references, adds some missing header fields and values, adds the beta support level, and includes various references in the readme.

How to test the Change

Utilize markdown previewer or GitHub web preview to see docs-related changes

Changelog Entry

n/a

Credits

Checklist:

• [x] I agree to follow this project's Code of Conduct.
• [x] I have updated the documentation accordingly.
• [ ] I have added tests to cover my change.
• [ ] All new and existing tests pass.