HTTPStatus::send406 never returns

- Create unexpected behaviors and bug

Lower code complexity.

- Make match method testable.

- Make class use of config more predicable by stop using
global conf.
- Make the class vital methods more testable.

Do not implement properties or code. It is a interface
and should be typed as one.

- Composer PSR-4 autoloading.

- Reduce logic complexity.
- Return early. Code get called on every request and should be fast.
- Remove support for mirroring multiple uri. Code uses a long gone
PHP function. Split this into a private method.

Cleanup that improve code readability.

- Paves way for real autoloading in the future.

- Always called utilities. We need to make sure they work
as expected. Introduce PHPUnit tests.
- Due to the use of gobals inside the static methods they
become untestable. Remove use of global but that also
forces a change if method signature.

Since there is no code style lets use PSR-12
https://www.php-fig.org/psr/psr-12/

- Fix static linked ARC2 lib in module code.
- Fix typo in index.php

- Improve readability

- Removed no longer needed inline comments.