Move logic from SDKs + Harness scripts to Sandbox

## Problem

Sandbox environment variables are overridden in the test harness and the SDKs which causes the repositories to be tightly coupled. If a new parameter is added to sandbox, or modified in some way, it must be propogated to 5 additional repositories.

Recently there was a major change which added conduit configurations. All of the sandbox configurations were updated, and tested as part of CI. All of the SDK tests were broken.

## Solution

The default sdk testing configuration should be a config file which is part of sandbox.
The logic in this repo should be stripped down to a bare minimum.
Any logic unique to this repository, like dumping errors on a failure, should become sandbox feataures.

## Dependencies

sandbox + SDKs

## Urgency