Rebrand README.md to Document Authoring

[bosschaert]

Description

Just a rebrand of the README.md file

Types of changes

• [X] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [X] I have signed the Adobe Open Source CLA.
• [X] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [X] I have updated the documentation accordingly.
• [X] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes.
• [X] All new and existing tests passed.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 52.89%. Comparing base (0a91468) to head (d10c6d5). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #81 +/- ## ======================================= Coverage 52.89% 52.89% ======================================= Files 38 38 Lines 1779 1779 ======================================= Hits 941 941 Misses 838 838 ```

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