tools: add babel-eslint

Create tools/update-babel-eslint.sh script and execute it to do the
first installation of the package.
Update tools/license-builder.sh and execute it to add babel-eslint's
license to our LICENSE file.

PR-URL: https://github.com/nodejs/node/pull/17820


Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>