Support js and native in core

[majk-p]

No description provided.

[adamw]

Let me know when this will be ready for review :)

[majk-p]

There seem to be too blockers now:

• tapir-apispec-docs are not cross-compiled, although all its dependencies seem to be native-ready
• ujson-circe is not cross-compiled, it seems to only depend on Circe which should be native 0.5.x ready, but I didn't have a close look

[adamw]

Ah :) Yeah we should be able to take care of tapir-apispec-docs quickly, if the dependencies are there.

[majk-p]

So the good part is that com-lihaoyi/upickle#680 is merged, bad side of it is that I somehow forgot to add JS so it's only native for now. When tapir-apispec-docs are ready we can start with SN support and contribute JS later.

[majk-p]

ujson circe js implemented in com-lihaoyi/upickle#681

[lbialy]

native done in #442