feat: support poetry v2

`poetry` v2 just got released: https://github.com/python-poetry/poetry/releases/tag/2.0.0

Let's add support for it and it's new features, if any
- new lock file format?
- any new `pytproject.toml` declarations
- support for PEP621 - metadata and dependencies
Goal: not either/or, but simultaneously the "old" `tool.poetry` and the "new" `project`
> Add support for the `project` section in the `pyproject.toml` file according to PEP 621
-- https://github.com/python-poetry/poetry/pull/9135
-- https://github.com/python-poetry/poetry/pull/9917
- investigate what else is new ... TBC ...
- ... TBC ...
- tests
- since poetry v2 there is a new lock file format in town: `2.1`. this means we can keep current test structures and add a new folder for each lockfile thing where needed.
- some new cases may not be available for older poetry - like the PEP621 in all its variants... -

[⤴ this list will be updated continuously based on comments below, until the initial feature was provided eventually]