Merge branch '461396-add-shardingkey' into 'master'

Add desired sharding key with backfill information

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/155598



Merged-by: Dylan Griffith <dyl.griffith@gmail.com>
Approved-by: Max Woolf <mwoolf@gitlab.com>
Approved-by: Dylan Griffith <dyl.griffith@gmail.com>
Co-authored-by: Shreyas Agarwal <sagarwal@gitlab.com>