Project general update

[verbman]

This Pull Request updates the OpenFisca Core dependancy to the latest version of OpenFisca Core. It also simplifies the project environment to leverage pyproject.toml (without reliance on poetry). The overall goal is to modernise the project from a python project perspective and improve the documentation.

• Technical improvement.
• Details:
  • Updated Documentation
  • Updated OpenFisca Core dependancy (to latest)
  • Updated python environment and version (3.11)
  • Updated docker related files
  • Updated github related files

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These changes :

• Impact the OpenFisca-Aotearoa public API (latest version via OpenFisca core)
• Change non-functional parts of this repository

[jadedarko]

Still looking this over, but my initial impression is that there are a lot of loosely related changes here that would arguably have been better as smaller, more focused PRs

[jadedarko]

Ultimately the only blocking change is that pipeline typo, the rest are simply suggestions

This is quite involved, you've made good ground on splitting the actions apart & updating the docs 👍🏼

One thing worth considering for future is the usage of black & moving away from the flake8 rules, as the code styles for this project are alien compared to most modern python projects (which will be using black)