Update and clarify documentation
- Split variable definitions into Terraform configuration and pipeline configuration for easier reading.
- Add example files for Terraform job variable configuration.
- Add links back to Terraform and Google Cloud documentation.
- Break up the continuous integration and Terraform README files into sections for easier perusal and linking.
Related: team-tasks#438 (closed)
Resolves: gitlab-org/omnibus-gitlab#4567 (closed)
Signed-off-by: Robert Marshall rmarshall@gitlab.com
Edited by Robert Marshall