Create terraform module for Google Cloud Postgres deployments

[stevenplatt]

Explain your changes:

• This code creates a terraform module that can be used to deploy an instance of Google Cloud postgres. The first use of this module has been to deploy a postgres instance to use as a backend for a prototype of a CI metric dashboard. To make that work reusable, the underlying terraform configurations were made abstract so that they could be used as a module within larger terraform deployments.

Explain how you tested your changes:

• This change was test by deploying a cloud postgres instance to Google Cloud. The features of this terraform module which were tested include:

• Assigning a label for billing purposes
• Pulling in a user password from Google Secret Manager
• Abstracting all configurations to variables for use in larger terraform deployments
• Appending a randomly generate name suffix to avoid deployment conflicts
• Printing the final IP address and user account credentials to the console for connecting to the deployed db
• Included initial README

Checklist:

• Dependency versions are unchanged
  • Notify Velocity team if dependencies must change in CI
• Modified the current draft of release notes with details on what is completed or incomplete within this project
• Document code purpose, how to use it
  • Mention expected invariants, implicit constraints
• Tests were added for the new behavior
  • Document test purpose, significance of failures
  • Test names should reflect their purpose
• All tests pass (CI will check this if you didn't)
• Serialized types are in stable-versioned modules
• Does this close issues? List them

• Closes #0000

[SanabriaRusso]

Nice step towards a (bright) templates-based platforms future