Keep track of PipelineArtifacts on storage usage page

Problem to solve

From #234032 (comment 400904884)

As a GitLab customer I want the storage usage page to keep track of pipeline artifacts so I can tell where my storage space is being used and know when I need to optimize my pipeline storage usage.

Right now pipeline artifact storage is taken into account in the Project statistics, but they are not represented on the storage usage page. Whether we make a separate entry for pipeline artifacts or join it with the existing artifacts in an Artifacts entry is up to product.

Intended users

• Delaney (Development Team Lead)
• Devon (DevOps Engineer)
• Sidney (Systems Administrator)

User experience goal

PipelineArtifacts are represented on the storage usage page.

Proposal

• Product to decide whether to create a new entry for Pipeline Artifacts separately or to join it with an Artifacts entry on the storage usage page

• Update the label from "Build Artifacts" to "Artifacts"

• Include in the tally both Job Artifacts and Pipeline Artifacts

Technical Proposal

• Add pipelineArtifactsSize to the GraphQL query
• Sum the number for buildArtifactsSize and pipelineArtifactsSize (probably in the apollo update function)
• Change the copy from Build Artifacts to be just Artifacts
• Add a question mark tooltip to display buildArtifactsSize and pipelineArtifactsSize individually.

Further details

The storage usage page is here: https://gitlab.com/profile/usage_quotas#storage-quota-tab

Permissions and Security

Documentation

• Update docs to include types of actions / resulting artifacts that contribute to this tally.
• Update docs with tips about how to keep this from overgrowing a users quota

Availability & Testing

What does success look like, and how can we measure that?

What is the type of buyer?

Is this a cross-stage feature?

Links / references