build: move ORCID to metadata in pyproject.toml, fix pixi (#3416)

Using ORCID in the authors/maintainers field was never really supported
(see
https://discuss.python.org/t/adding-extra-fields-in-the-pyproject-toml-authors-maintainers-list/16848/12
for discussion), and now is actively breaking `pixi`.

Move it to `metadata` key instead.

Also track extras ("test", "demo", "doc", "storage", "all") in the pixi
default environment, which makes the pixi.lock more reproducible.