Ensure `environment` keyword is defined in GitLab CI/CD templates

Problem

Our CI/CD templates can be more powerful if it uses Environments and deployments features, which requires environment keyword to be defined to deployment jobs.

Proposal

Define environment keyword in GitLab CI/CD templates. For more information, see Development guide for GitLab CI/CD templates.

Missing deployment job

The following templates are missing deployment jobs. We should create a placeholder deploy job and define environment: production. e.g.

deploy:
  stage: deploy
  script: echo "Define your deployment script!"
  environment: production

Has a deployment job, but missing environment keyword

The following templates have a deployment job, but missing environment keyword. We define environment: production to the job. e.g.

deploy:
  ...
  environment: production

Has a pages job as deployment, but missing environment keyword

The following templates have a pages job as a deployment, but missing environment keyword. We define environment: production to the job. e.g.

pages:
  ...
  environment: production
Edited by Shinya Maeda