n-api,src: provide asynchronous cleanup hooks

Sometimes addons need to perform cleanup actions, for example
closing libuv handles or waiting for requests to finish, that
cannot be performed synchronously.

Add C++ API and N-API functions that allow providing such
asynchronous cleanup hooks.

Fixes: https://github.com/nodejs/node/issues/34567

PR-URL: https://github.com/nodejs/node/pull/34572


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gabriel Schulhof <gabriel.schulhof@intel.com>