adb host as parameter

[QAutomatron]

JadbConnection supports using an external host for adb commands. It would be nice to have an option to set it from Gordon configuration.

Use cases: access host machine from docker container. Or access devices from another host in network.

[joshschriever]

As of #39 we also use bundletool for installs, and I don't think that supports external adb host yet. There's a PR for it, but that's stale. Hopefully eventually we can support this somehow.

[sleekweasel]

An alternative to telling bundletool how to talk to remote hosts that I didn't pursue because I got my patch working: run a proxy forwarding socket, something like 'socat', to give yourself a local port that connects to the remote machine.

[joshschriever]

@QAutomatron As of #95 (released in v1.7.0), we got rid of jadb and started using bundletool for everything. Bundletool should respect the ANDROID_ADB_SERVER_PORT env variable if set, so using that along with something like socat, as @sleekweasel mentioned, could work.