Flasksimpleauth

- Add _Python 3.13_ and _Pypy 3.10_ to CI.
- Given its lack of maintenance, remove the mandatory dependency to `passlib` for default `bcrypt` scheme by implementing the password check directly.
- Add support for password scheme `argon2` and `scrypt`.
- Add direct implementations for `plaintext`, `a85` and `b64`: the two later schemes are simple obfuscations proposed as _better_ very bad options over `plaintext`.
- Add support for `passlib` list of schemes.
- Add `FSA_AUTH_DEFAULT` to require a specific authentication scheme by default.

- Force `text/plain` on empty results, because it is most likely _not_ a valid whatever (json, html)…
- Update and extend demo with pydantic example.
- Update README.
- Allow mixing _JSON_ and _HTTP_ parameters.

- Simplify tutorial code.
- More precise warning.
- Check with `ruff`, drop check with `mypy`.

- Improve tutorial.
- Fix unformatted format strings.
- Add convenient `err` function for `raise ErrorResponse`.

- Test cookie with a string default.
- Rename predefined special groups: `OPEN AUTH CLOSE`.

- Fix handling of default str values for headers and cookies special parameters.
- Also show cookies in debug mode.