Set Sidekiq Cluster process count to CPUs
Relates omnibus-gitlab#5797 (closed) omnibus-gitlab#6085 gitlab-org/quality/reference-architectures#49 (closed)
MR updates Sidekiq config (omnibus) to set Sidekiq queue_groups
(aka processes or workers) to the same number as CPUs as each process will ever only use 1 CPU (like Puma).