tools: add script to update c-ares

Add a script to automate updating of the c-ares dependency and
accompanying maintenance guide.

PR-URL: https://github.com/nodejs/node/pull/40660


Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Michaël Zasso <targos@protonmail.com>