recipetool/create_buildsys_python: add PEP517 support

recipetool/create_buildsys_python: add PEP517 support

Add basic support for PEP517 [1] for the 3 following backends that are
supported by bitbake:
  - setuptools.build_meta
  - poetry.core.masonry.api
  - flit_core.buildapi

If a pyproject.toml file is found, use it to create the recipe,
otherwise fallback to the old setup.py method.

Some projects can declare a minimal pyproject.toml file, and put all
the metadata in setup.py/setup.cfg/requirements.txt .. theses cases
are not handled. If a pyproject.toml file is found, assumes it has all
necessary metadata.

As for the old setup.py method, version numbers for dependencies are not
handled.

Some features may be missing, such as the extra dependencies.

[YOCTO #14737]

[1]: https://peps.python.org/pep-0517/

Signed-off-by: Julien Stephan <jstephan@baylibre.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>