Add terraform report to merge request widget

Goal

Provide a summery of terraform plan in the merge request widget

Designs

Definition of Done

• Add the terraform plan report to the merge request widget that matches the Designs
• Widget should show added/changed/removed resource counts
• Widget should link to job log
• Update https://gitlab.com/gitlab-org/gitlab/blob/master/lib/gitlab/ci/templates/Terraform.gitlab-ci.yml to artifact the report automatically