Merge branch 'as/cells-infra' into 'master'

Blueprint for Cells Database Infrastructure

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/144238



Merged-by: Steve Xuereb <sxuereb@gitlab.com>
Approved-by: Steve Xuereb <sxuereb@gitlab.com>
Approved-by: Andrew Newdigate <andrew@gitlab.com>
Reviewed-by: Steve Xuereb <sxuereb@gitlab.com>
Reviewed-by: Biren Shah <bshah@gitlab.com>
Co-authored-by: Rachel Nienaber <rnienaber@gitlab.com>
Co-authored-by: Alexander Sosna <asosna@gitlab.com>
Co-authored-by: Andrew Newdigate <andrew@gitlab.com>