Link to packages providing additional tools for building N-API/node-addon-api addons

[gabrielschulhof]

Tools for easing validation of values coming in from JS is proposed in #639. We have chosen not to integrate these tools, however, we should provide (at least) a link on the documentation page pointing folks to tools which are available in addition to node-addon-api that will help them build native addons using N-API.

[github-actions]

This issue is stale because it has been open many days with no activity. It will be closed soon unless the stale label is removed or a comment is made.