Python 3.11 comes with built-in support for TOML. It's an almost direct
import of the tomli package. As the 'toml' library is unmaintained, and
tomli has the same interface as what's in the standard library, this
switches the TOML support to a supported library with a minimum of fuss.

Tomllib requires files to be opened in 'rb' mode, so the relevant tests
had to be updated accordingly.

In most cases conventional "python-" prefix used in project names is
not used in exported module names. However, there are some exceptions
and we have to account for that.

Fixes arkq#74

Closes arkq#71

Fixes arkq#76

The dynamic dependencies are part of pep621.
For now only the setuptools supports dynamic dependencies.
Because of that the implementation is somehow dependent on setuptools.
When other tool adds support for dynamic dependencies
only the part for gathering of the dependencies has to be changed.

Fixes arkq#92