Move logic from SDKs + Harness scripts to Sandbox

[winder]

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