Expose arguments and env to launch_app

[oxcug]

Hey folks, looks like the rpc call for launching an app hard-codes the args and env parameters. Can these be exposed? Happy to put up a PR. Code in question:

    pid = _rpc_channel.call(channel_name,
                            "launchSuspendedProcessWithDevicePath:bundleIdentifier:environment:arguments:options:", "",
                            bundle_id, {}, [], {"StartSuspendedKey": 0, "KillExisting": 1}).selector

[YueChen-C]

I think it can be exposed. Welcome to submit a pr