docs: restructure README and update config namespace

[jordikroon]

This will shift the docs to GH pages. Also allowing us to define an XML Schema Definition (XSD) file.

[github-actions]

PHPUnit 13.1.7 by Sebastian Bergmann and contributors.

Runtime:       PHP 8.5.5 with Xdebug 3.5.1
Configuration: /home/runner/work/docbook-cs/docbook-cs/phpunit.xml.dist

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Time: 00:00.941, Memory: 24.00 MB

OK (266 tests, 462 assertions)

Generating code coverage report in Clover XML format ... done [00:00.006]

Generating code coverage report in HTML format ... done [00:00.133]


Code Coverage Report Summary:
  Classes: 100.00% (25/25)
  Methods: 100.00% (140/140)
  Lines:   100.00% (958/958)