Merge branch 'sc1-optimize-concurrency-tracking' into 'master'

Track worker concurrency using Redis hash - 2nd try

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/169561



Merged-by: Stan Hu <stanhu@gmail.com>
Approved-by: Dmitry Gruzd <dgruzd@gitlab.com>
Approved-by: Stan Hu <stanhu@gmail.com>
Reviewed-by: Dmitry Gruzd <dgruzd@gitlab.com>
Reviewed-by: Sylvester Chin <schin@gitlab.com>
Co-authored-by: Sylvester Chin <schin@gitlab.com>