feat: smart /api/v0 handling

[hacdias]

Closes #13. I also implemented @aschmahmann comment regarding dag/export. I checked the API and there are no additional options that could lead to incompatibilities. The only option is progress which is useless for remote calls.

[lidel]

Thank you, this should be good enough for Feb 17.
(if redirect is too slow for resolve ones, we can add local cache later)