[DOC] Request: guidance on system requirements for building cudf locally

## Report needed documentation

**Report needed documentation**

CONTRIBUTING.md documents compiler and cuda requirements but doesn't mention hardware requirements for building from source. As someone trying to provision a cloud vm to build my changes, I had to figure out a configuration through trial and error, and I'm still not 100% confident I have the best possible setup.

**Describe the documentation you'd like**

It would be helpful to document minimum RAM (32gb has been working for me), as well as recommended number of cores, and recommended disk space (I need at least 15-20gb I think).

Even better would be a table of rough estimates of configurations -> build time so we could see how it scales with more memory/cpu.

As a start, how beefy are the CI machines?

**Steps taken to search for needed documentation**
List any steps you have taken:

- I read through CONTRIBUTING.md
- I asked claude to read through everything in this repo, search the internet, see if it can find any hints on how big of a toaster it would need to provision in order to build cudf in a reasonable time. It came up empty.