Consolidate all docker images used by omnibus-gitlab in one place
Currently, images used for omnibus-gitlab's spec jobs are stored in https://gitlab.com/gitlab-org/gitlab-build-images/ while the ones required for building packages are stored in https://gitlab.com/gitlab-org/gitlab-omnibus-builder. This results in two MRs being needed while adding support for a new OS.
Proposal: Let's move all of them (just the images used by omnibus-gitlab test pipelines - not the entire repo) to https://gitlab.com/gitlab-org/gitlab-omnibus-builder, so that they can be updated in a single MR.
Edited by Balasankar 'Balu' C