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.

• Ask infrastructure team on .com how they would love to configure sure allow-lists to allow requests from the rails app to fix Intermittent SSL_connect SYSCALL on GitLab.com (gitlab#381312 - closed) • Unassigned • Backlog
• Add documentation
• Once this is released, make sure we configure these allow lists for .com