feat: Set up the project using poetry & limit the dependency list to top level

[Raff-dev]

There is that tool called Poetry. It can manage dependencies, create virtual environments as well as build packages.
It is convenient as you don't need to add dependencies to requirements.txt, poetry does this for you in pyproject.toml file.
It handles dependency resolution and downloads the dependencies in parallel, which makes it faster.

It is widely used across many new python projects including AutoGpt

The dependency list before was probably a result of pip freeze > requirements.txt, which is kind of unnecessary, as we would like to pin only the packages we depend on.