build: use `CARGO` environment variable if set

When enabling support for Temporal, check for the `CARGO` environment
variable to locate the `cargo` binary (defaulting to `cargo` if not
set) and use this to build `deps/crates`.

This will allow using Cargo on systems where the Cargo binary name is
suffixed with the version, e.g. `cargo-1.82` on Ubuntu 24.04.

PR-URL: https://github.com/nodejs/node/pull/62421
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Marco Ippolito <marcoippolito54@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>