Cross-publish core module

[jisantuc]

Overview

This PR cross-publishes core for Scala.js. Or, you know, it will eventually.

Checklist

• New tests have been added or existing tests have been modified
• Changelog updated

Notes

All TODOs done! 🎉

I'm pretty sure that the local publication proves that sonatype publication should Just Work ™️, but if there's other evidence to gather about that, I'm happy to gather it.

Right now I'm working on getting types lined up to have a js module that works. The main focus so far has been on adding a Geometry type that doesn't depend on GT. I'm only bothering for now with 2d points, polygons without holes, and multipolygons. To get tests running I'm also going to add some optics, because it turns out monocle publishes for Scala.js and some prisms will make my tests nicer to write. Once I have a SerDeSpec for the geometry types I'll work on actually publishing, which I don't uh technically know how to do yet (though maybe the nice sbt plugins will take care of that bit).

Next TODOs:

• export some types to see if they end up in the fastoptjs file as i expect
• get tests actually running
• add node to ci environment
• add an extent type to make geom generation less haphazard

Update 2020/11/11: I'm working now on porting everything that depends on java.time into the JS side. This library makes it look like I can add a dep and then just use the same java.time API, but I'm getting a lot of complaints in test runs about Referring to non-existent class java.time.format.DateTimeFormatter and other classes, so I'm suspicious. I think the JS side is just going to need to be more ad hoc about time types for now. You can see failures in this build output.

Next TODO:

• move ForeignImplicits out of shared SerDeSpec because I don't understand what it will pull in there (I assume the cross-project appropriate package?)
• choose a time library, like https://github.com/zoepepper/scalajs-jsjoda maybe scala-java-time works fine as long as it's declared as a dep not only in both core and coreTest 🎉

Testing

• run test from root and see that you get all the tests from JVM and JS sides
• run publishLocal from root and see that you publish both JVM and JS sides to local cache

Closes jisantuc/fp-http-azavea-rd#3

[pomadchin]

Project works and this is a nice change towards JS support 🎉

My main concerns are only about the code duplication. Is it possible to avoid it as much as it is possible? Theoretically we could only try to substitude Geometry and that can solve all JS compilation issues, rather than creating lots of classes duplicates. It is also possible to move specific to platform methods into syntax extensions.

@jisantuc have you considered that? do you know is it possible?