Istio installer is a modular, 'a-la-carte' installer for Istio. It is based on a
fork of the Istio helm templates, refactored to increase modularity and isolation.

Goals:
- Improve upgrade experience: users should be able to gradually roll upgrades, with proper
canary deployments for Istio components. It should be possible to deploy a new version while keeping the
stable version in place and gradually migrate apps to the new version.

Installations from other installation methods (such as istioctl, Istio Operator, other helm charts, etc) can be migrated to use the new Helm charts
following the guidance below.
If you are able to, a clean installation is simpler. However, this often requires an external IP migration which can be challenging.