android support

[oli-obk]

isahc is not easily usable on android, because it always uses openssl and doesn't have a published version that can opt-out of that (sagebind/isahc#199).

I read #18 (comment), but it's not clear to me why isahc was preferred over surf, when both appear to not have the issue with loading some urls.

I can do the work and switch back to surf (and set it up so it works with rustls) if that is ok with y'all

[johanhelsing]

I'm ok with that. I think they're both unmaintained, which is unfortunate, but i also prefer surf.