Document workflow for deploying a newer version of a package onto an existing zarf clusters

[AustinAbro321]

Is your feature request related to a problem? Please describe.

Currently we don't have much on the docs site explaining how zarf clusters in should be updated in the day two scenario. I believe, it should just be redeploying the init package, then the new zarf package, but we should make sure that info is easy to find. We should also talk about rolling back the deployment of a package to an earlier package. Not sure if there are any pitfalls there or other common day two "traps" one might fall into.

The best practices page proposed in #1684 could be a decent spot, otherwise we could have a page dedicated to day two advice