Some downstream distros fail to compile Prometheus UI (Debian, NixOS).
This is an attempt to store compiled UI in circleci for them to consume
it. Currently we do not expose this outside of circleci.
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
Co-authored-by: Julien Pivotto <roidelapluie@o11y.eu>