Allow to configure allow-list for CIDRs to exclude them from rate-limits
### Summary Idea from https://gitlab.com/gitlab-com/gl-infra/production/-/issues/6087#note_794032931. We may want to allow some IP's/IP ranges (CIDRs) to bypass the rate-limits. The same is for domains. * [x] Ask infrastructure team on .com how they would love to configure sure allow-lists to allow requests from the rails app to fix https://gitlab.com/gitlab-org/gitlab/-/issues/381312+s * [x] Pages Implementation: https://gitlab.com/gitlab-org/gitlab-pages/-/issues/1128 * [x] Pages version upgrade * [x] Omnibus configuration: https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/8649 * [x] Charts configuration: https://gitlab.com/gitlab-org/charts/gitlab/-/issues/5678 * [x] Add documentation: https://gitlab.com/gitlab-org/gitlab/-/issues/474827 * [x] Finalize subnets to add to bypass allow list: https://gitlab.com/gitlab-org/gitlab/-/issues/478915 * [x] Configure these allow lists for .com: https://gitlab.com/gitlab-com/gl-infra/k8s-workloads/gitlab-com/-/merge_requests/3833
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