Pipeline Template Enhancements

[VonnyJap]

Placeholder for feature requests on pipeline template:

• [ ] Improve docs to outline specs
• [x] Support pipeline level config:
  • [x] cache: https://github.com/screwdriver-cd/screwdriver/issues/3058
  • [x] annotations, parameters, subscribe
  • [x] stages
• [x] Support customization of pipeline level config
  • [x] annotations, parameters
  • [x] cache
  • [ ] subscribe
• [x] Enable users utilizing pipeline templates to customize image, settings, environment, and requires under shared configuration
• [x] Enable users utilizing pipeline templates to customize image, settings, environment, and requires within the job configuration
• [x] Ability to add new jobs in the pipeline using a pipeline template
• [ ] Pipeline Template Usage metrics
  • [ ] Add a new metric to show how many pipelines are using a template across all the versions
  • [ ] Add a new metric to show how many pipelines are using a specific version of a template
  • [ ] Add a new metric to show how many events used the pipeline template across all the versions
  • [ ] Add a new metric to show how many events used a specific version of a template
• [ ] Customization of pipeline template job config (either under shared or individual jobs)
  • [ ] parameters, annotations, cache, freezeWindows, secrets
  • [ ] provider
  • [ ] sourcePaths
  • [ ] blockedBy, description
  • [ ] template
  • [ ] steps, order
• [ ] Support for more pipeline level config when a pipeline uses the template:
  • [ ] childPipelines
• [ ] Nested Pipeline Template

[kumada626]

I think it would be nice if the settings field could also be customized to configure notifications via pipeline shared config and pipeline job config.