Split queues for Sidekiq chart

Allow configuration of multiple/split queues for the Sidekiq chart.

As discussed in #53 (closed)

• Multiple Deployments
• Multiple ConfigMaps paired to the Deployment
• One shared ConfigMap for database configuration.

The configuration YAML structures are as laid out in the description of #53 (closed), with the addition of support for individualized resources and nodeSelector values.

gitlab:
  sidekiq:
    pods:
      - name: recv
        replicas: 2
        queues:
          - [post_receive, 5]
          - [merge, 5]
          - [update_merge_requests, 3]
          - [process_commit, 3]
      - name: recv
        replicas: 1
        resources:
          requests:
            cpu: 100m
            memory: 2Gi
        nodeSelector:
          sidekiq-priority: high
        queues:
          - [new_note, 2]
          - [new_issue, 2]
          - [new_merge_request, 2]
          - [build, 2]

This set of changes is in addition to !16 (merged), in order to keep !16 (merged) less complicated in terms technical involvement. (cc @marin)