Restrict database access URL to required services only in awstf

[jyecusch]

Feature Request

Suggestion

Currently, all services in a deployed stack will have access to the NITRIC_DATABASE_BASE_URL env var. This environment variable should ideally only be added to services that have requested access to the database in the deployment spec.

Value

Slightly improve least-priveledge access control

Other info

See: cloud/aws/deploytf/service.go:56