Introduce a NodeTarget inspector domain modelled after ChromeDevTools
Target domain. It notifies inspector frontend attached to a main V8
isolate when workers are starting and allows passing messages to
inspectors on their isolates. All inspector functionality is enabled on
worker isolates.
PR-URL: https://github.com/nodejs/node/pull/21364
Reviewed-By: Aleksei Koziatinskii <ak239spb@gmail.com>
Reviewed-By: Jan Krems <jan.krems@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
