Add prod stage in CD pipeline

[nancywen25]

As a developer I need to add prod stages in CD pipeline So that when after all test passes, the service is deployed to prod

Assumptions:

• build & dev stages have already been added to the pipeline
• there is a dev space, but a prod space still needs to be added

Acceptance Criteria:

Given the four stage pipeline
When that the app passes all previous stages (unit tests + BDD tests)
Then the app will be deployed to prod