Make CI artifacts to be stored on object storage
Following the discussion from here: https://gitlab.com/gitlab-org/gitlab-ce/issues/26897 it seems that artifacts do grow significantly and it is also harder and harder. We should use CarrierWave and feed that with possibility to point to external storage (S3/AWS).
Documentation blurb
As companies continue to embrace CI/CD across the organization, their artifact storage needs naturally increase as well. With GitLab 9.3 we are proud to announce that CI artifacts can now be saved to object storage, like Amazon S3 or Google Cloud Storage. Leveraging these cloud services enables artifacts to be saved cost effectively, reliably, and with nearly infinite scalability.