Add Cloud Native installation steps to Reference Architecture tiers

We added a note a little while back to help give some initial guidance around Cloud Native led reference architectures 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