js/{closure,commonjs}: create a new js_module option

[glerchundi]

What language does this apply to?

If it's a proto syntax change, is it for proto2 or proto3? proto3
If it's about generated code change, what programming language? javascript/commonjs but it can be applied to es6 or closure as well.

Describe the problem you are trying to solve.

We are generating code of multiple packages that we want to publish independently but with references between them. Currently the generator creates a tightly coupled relative paths between folders.

Describe the solution you'd like

An option like Go's go_package or C#'s csharp_namespace where I can put the import path, in this case the JS module.

I think a js_module called option would do the trick.

Describe alternatives you've considered

Overriding the generated code.

[glerchundi]

@xfxyjwf friendly ping!

[aberasarte]

Any update on this ?

[glerchundi]

Another friendly ping to @anandolee @TeBoring @BSBandme!

[glerchundi]

This is related to protocolbuffers/protobuf#2198, is it possible any maintainer give us a status update or how they think this can be solved/workaround?

We want to start collaborating with envoyproxy/lyft and its protoc-gen-validate and this would open up the possibility to make it happen.