Avielle Wolfe authored Jun 04, 2020 and Shinya Maeda committed Jun 04, 2020

1. It was weird that a key named `artifacts` returned builds
2. We need BuildArtifactEntity to represent each artifact of a job in
    order for a job to have more than one downloadable artifact
3. We need BuildArtifactEntity to have access to an artifact's file type
    in order to properly create the download path