Adds IaC for GCP

[daschwanden]

Fixes #138

It's a good idea to open an issue first for discussion.

• [ * ] Tests pass
• [ * ] Appropriate changes to documentation are included in the PR

[Brandon Royal (brandonroyal)]

Thanks for the PR Dan! Since this is GCP specific, I might suggest placing in a gcp subfolder. It's also worth a community discussion on whether TF should existing within the project itself or a separate repo

[Benjamin Elder (BenTheElder)]

Also slightly concerned about keeping this in sync with the imperative GCP setup tool. cc Tim Hockin (@thockin) Dmitry Berkovich (@dberkov)