Support Redis cluster configuration for registry rate-limiting

What does this MR do?

While testing the Redis rate-limiting configuration on pre (gitlab-com/gl-infra/k8s-workloads/gitlab-com!3727 (merged)), we found that the chart will append a port to the last host on a list like the following:

Before

values.yml:

  redis:
    rateLimiting:
      enabled: true
      host: 'redis.one.example.com:6379, redis.two.example.com:6379'

Rendered configuration:

    redis:
      ratelimiter:
        enabled: true
        addr: "redis.one.example.com:6379, redis.two.example.com:6379:6379"

To support using a Redis cluster, we want to add a subsection registry.redis.rateLimiting.cluster to the registry configuration.

After

  redis:
    rateLimiting:
      enabled: true
      cluster:
        - host: 'redis.one.example.com'
          port: 6379
        - host: 'redis.two.example.com'

Rendered configuration:

    redis:
      ratelimiter:
        enabled: true
        addr: "redis.one.example.com:6379, redis.two.example.com:6379"

Related issues

Closes Registry: Add support for Redis cluster addresses (#5650 - closed)

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• Equivalent MR/issue for omnibus-gitlab opened.

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• MR has a green pipeline on https://gitlab.com/gitlab-org/charts/gitlab.
• Consider downstream impact to the Operator, as per evaluating impact from changes to GitLab Chart.