Need an API to download any (internal?) job artifact type

Problem to solve

Currently only traces are able to be downloaded from this API. However, other internal types, such as junit, metadata, metrics_referee, and network_referee (types added by this MR), lack an API for download.

Intended users

• Sidney (Systems Administrator) - a power user that wants to extract these resources
• Sam (Security Analyst) - a security expert that wants these resources for security analysis