Integrate API Gateway script into Nightly CI Deploys

[galenatjpl]

Creation of empty REST API, into the API Gateway, so that SPS endpoints can then be added/utilized later.

See also:

https://github.com/unity-sds/unity-cs/tree/api-gateway-terraform/terraform/terraform-api-gateway

Acceptance Criteria:

• Verify the REST API gets deployed to the API Gateway
• Verify specific SPS API routes get populated into the REST API as part of the nightly.
• For this phase, the SPS endpoints that need to be publicly accessible from the perspective a human and/or service API, need to be properly routed/exposed.

[ramesh-maddegoda]

Created pull request unity-sds/unity-cs-infra#12 to add terraform scripts of API Gateway and Cognito user pool