console: add support for console.debug

Adds the console.debug() method, alias for console.log(). This method is
exposed by V8 and was only available in inspector until now. Also adds
matching test and documentation.

PR-URL: https://github.com/nodejs/node/pull/17033
Refs: https://github.com/nodejs/node/pull/17004


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Khaidi Chu <i@2333.moe>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>