A recent group of vulnerabilities have been found in Pleroma (and
inherited by Akkoma) that involve media files either uploaded by local
users or proxied from remote instances (if media proxy is enabled).
It is recommended that media files are served on a separate subdomain
in order to mitigate this class of vulnerabilities.
Based on https://meta.akkoma.dev/t/another-vector-for-the-injection-vulnerability-found/483/2