npx gitwho automatic binary selection per arch

## Problem being solved
Each machine uses a different os/arch, so we need a different binary running. npx/npm was built for portable software, so we have to come up with a solution for using npx along with gitwho.

## Proposal
We already have different os/arch combinations published as different packages in npm. Enhance the base gitwho package to make an automatic binary installation of the appropriate binary.

https://www.npmjs.com/package/gitwho
https://www.npmjs.com/package/@gitwho

Check files at /npm in repo

See: https://github.com/evanw/esbuild/blob/main/lib/npm/node-install.ts for an example