Bundle docker distribution pruner
This adds a bundling of Docker Distribution Pruner into Omnibus.
Needed CE change: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/24174.
Resolves #4021 (closed).
Part of: docker-distribution-pruner#20 (closed) needed as part of https://gitlab.com/gitlab-org/gitlab-ce/issues/25322.
Edited by GitLab Release Tools Bot