Update Sidekiq chart queues based on routingRules

What does this MR do?

Since we updated default routing rules in Rails gitlab-org/gitlab!97908 (merged), now we need to update the default queues listened by Sidekiq. This MR updates SIDEKIQ_QUEUES based on the following condition:

• Defaults to 'default,mailers' unless global.appConfig.sidekiq.routingRules is set.
• Generate SIDEKIQ_QUEUES based on the queues listed in routingRules if set.
• User can still customize SIDEKIQ_QUEUES in the Sidekiq chart per pods values (Existing condition)

Related issues

• gitlab-com/gl-infra/scalability#1930
• gitlab-com/gl-infra/scalability#1491

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion.

Required

• Merge Request Title and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com
• When ready for review, MR is labeled "~workflow::ready for review" per the Distribution MR workflow

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• Documentation created/updated
• Tests added
• Integration tests added to GitLab QA
• Equivalent MR/issue for omnibus-gitlab opened
• Validate potential values for new configuration settings. Formats such as integer 10, duration 10s, URI scheme://user:passwd@host:port may require quotation or other special handling when rendered in a template and written to a configuration file.