nixguix: Filter out unsupported artifact extensions

Instead of trying to download artifacts and then break on ingestion. Try to
prevent spurious downloads which cost too many wasted resources (both upstream
servers and our own infra) and many noisy issues in sentry.

Ideally, we should improve our archive support. In the mean time, this approach
allows more sensible treatment than the current approach (see previous points).
This will also allows to incrementally add support, and demonstrating it by
removing the new supported archive pattern in the current regexp in next
commits.

Related to T2510