WIP: Add vrange JSON files from server & client

What does this MR do?

Add vrange-compatible JSON files based on what's returned by the Gemnasium API, and process them using vrange CLIs. These correspond to file extension .vrange.server.json and .vrange.client.json, respectively.

This is used to compare the affected and unaffected versions with the ones found by the new Gemnasium implementation using gemnasium-db. See gitlab-org/security-products/analyzers/gemnasium!25 (merged)

WARNING! DO NOT MERGE!

Related issues

gitlab-org/gitlab#14630 (closed)

/cc @julianthome