N-API: add error code to error creation methods

[mhdawson]

• Version: ALL
• Platform: ALL
• Subsystem: ALL

As part of the push on #11273 we should encourage the good practice of providing a code separate from the message on errors created by N-API modules. Since the modules don't have access to the internal list of errors they will not necessarily use the same error codes/templates, but it will still encourage good practice and could be useful if N-API is later used to implement internal modules.

This would likely be by adding an optional code value to existing APIs like napi_create_error.

[mhdawson]

I'm going start on this later today.