Add Cloud Native installation steps to Reference Architecture tiers
<!--- GitLab Performance Issue Tracker - Raise Issues here relating to the GitLab Performance Tool (or associated projects) as well as any performance test requests. ---> [We added a note a little while back to help give some initial guidance around Cloud Native led reference architectures](https://docs.gitlab.com/ee/administration/reference_architectures/#configuring-select-components-with-cloud-native-helm) but requests keep coming in about perhaps some more guidance, specifically some around actual Helm sizing for at least the bigger reference architectures - which we've already looked at a little internally. This could be doable now with the latest docs setup, we could have an alternative table with guidance on standard Helm sizes for Rails, Sidekiq etc... cc @WarheadsSE
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