gyp: implement LD/LDXX for ninja and FIPS

The ability to set the link rule is used for FIPS, and needs to set
both the `ld =` and `ldxx =` variables in the ninja build file to link
c++ (node) and c (openssl-cli, etc.) executables.

URL: https://github.com/nodejs/node/pull/14227


Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>