Change package manager from Hatch to Poetry

[schulz-m]

As other projects in the fractal code seem to use Poetry as well, I would love if the template can switch :-)

[jluethi]

In my experience, poetry brings some extra complexity that most of our power users aren't used to and poetry isn't a tool that's well established in biology / bioimage analysis.
Given that the template is meant to make it easy for power users & not just for developers, using tooling that keeps their life simple is a priority. I'm also not personally very used to poetry and thus can't easily onboard people to its idiosyncrasy. Thus, we are not currently considering using poetry more broadly.

For further context: we're not using poetry internally at the BVC in new libraries we build like ngio. And there are also some discussions on whether tasks-core will always stay in a poetry setup. cc @lorenzocerrone . But that won't change too fast :)