AI use

• Initial code from ChatGPT, but at the end, all the code excepted for hashes is rewritten by hand
  • Notably, marker search from GPT model was using regexp, but we belong to the sect "use regexp where it makes sense, not everywhere"
• JetBrains PyCharm autocomplete feature worked like a charm in the README, to help to structure the list of options or the table. Less for the description part, mostly human-written.

Vault authentication

With this change, it works when run with a default Vault configuration, for example VAULT_TOKEN defined in environment. So humans can run it, but it's not yet service-ready.

I wrote this evening a new library called secretsmith, a wrapper on the top of hvac, to configure Vault as we want from a configuration file.
This library is generic enough we can publish it on PyPI.