refactor: update package strategy in rest_api

[masci]

Related Issues

Part of: #3085

At this moment it's not possible to install rest_ui unless it's in editable mode, which prevents optimising Haystack's Dockerfiles.

Proposed Changes:

Refactor the packaging so that rest_api can be properly installed

How did you test it?

pip install /path/to/haystack-repo/rest_api

Notes for the reviewer

Checklist

• I have read the contributors guidelines and the code of conduct
• I have updated the related issue with new insights and changes
• I added tests that demonstrate the correct behavior of the change
• I've used the conventional commit convention for my PR title
• I documented my code
• I ran pre-commit hooks and fixed any issue

[ZanSara]

Looks good 👍

Overall I found only a few links to fix, one minor question mark, and I'm super interested about __about__.py for some reason 😄

[ZanSara]

Wow, this is new!

I've googled it quickly and found some references in SO, but no official docs. Is it a style choice or something actually recommended for packages? I like it, and if it's a standard I'd like to see it in Haystack as well someday in place of the VERSION.txt file 🤩

[masci]

I don't think it's standard but it looks like a good practice. I got it from the default template used by hatch when you bootstrap a new project, it can be definitely ported to Haystack at some point

[ZanSara]

👍