update README, correct HTML links, cleanup

[durack1]

Description

Correcting some HTML link loose ends. Cleanup redundant headers in README.md

Checklist

Please confirm that this pull request has done the following:

• [ ] Documentation added (where applicable)
• [x] Changelog item added to changelog/

Fix #107

[github-actions[bot]]

No changes to the database between 'main' branch and 45f076c6c04d38216c443e45b33e2479d5b84dd1