test-infrastructure: handle inter-stack dependencies without stack exports

[malachi-constant]

CloudFormation Outputs in test infra are causing circular dependencies. Switch to SSM
https://github.com/aws/aws-sdk-pandas/blob/release-3.0.0/test_infra/app.py#L48

[malachi-constant]

Adding SSM parameters first. Will proceed with swap in dependent stacks and then come back to delete exports. Code changes tracked in #2009

[malachi-constant]

Closed in #2009 & #2020