move most project metadata into pyproject.toml

Contributes to #115

Proposes moving most project metadata into pyproject.toml.

Notes for Reviewers

I found this helpful while working on this: https://scikit-build.readthedocs.io/en/latest/usage.html

Benefits of these changes

allows dependency lists to automatically be managed via rapids-dependency-file-generator (and single-sourced from dependencies.yaml)
will help reduce duplication between metadata for wheels and for conda packages
- e.g. like this: https://github.com/rapidsai/rapids-build-backend/blob/cb2dedbb8532739822378811e4adbab06514f582/conda/recipes/rapids-build-backend/meta.yaml#L23-L25

Why can't we completely eliminate `setup.py`?

I think it's possible and I'm planning to try it, just trying to do this in small-enough-to-thoughtfully-review chunks.

How I tested this

On a machine with CUDA 12.2 (R535 driver) and 8 V100s, I tried all the different installation and testing paths described in README.md and contributing.md.

I also built a wheel like this

ci/build_wheel.sh

And manually inspected it like this:

# list all the contents
unzip -l dist/*.whl

# check the metadata looked right
pkginfo --simple dist/*.whl

# check for portability problems
pydistcheck --inspect dist/*.whl

(pydistcheck (link) is my little side-project for testing the contents of Python package distributions)

rapidsai / legate-boost