Revert "Add instance-level maven endpoint for download"
What does this MR do?
Reverts https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/8274 because of https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/8274#note_123258127. Need to change the data model first to ensure package path uniqueness.
What are the relevant issue numbers?
Edited by Dmytro Zaporozhets (DZ)