Document Community addon onboarding path

To help users (who may only have light Istio knowledge) onboard with the new Istio/Sail operator, we should document an onboarding path that gets users to a similar starting point as a user installing OSSM2 - for the purposes of development and experimentation on OpenShift. This should use upstream Istio / community components, rather than product components.

This documentation should live in the Operator Git Hub, and though should be tested on OpenShift with any extra steps for OpenShift noted.

This includes:

• Install Istio (done - though should be able to specify a version; Update any operator changes)
• Install Istioctl (link to Github page - will install latest version, should align with version in last step)
• Install Istio Gateway (with an example config + expose gateway via OCP route) done
• Install Bookinfo (use community yaml; verify can access web page via OCP route) done
• Install Prometheus (Istio addon + anyuid correction + istioctl dashboard grafana)
• Install Grafana (Install addon + anyuid correction + istioctl dashboard grafana)
• Install Jaeger (Install addon + istioctl dashboard jaeger)
• Install Kiali (Install addon + istioctl dashboard kiali)

Refer to upstream doc where helpful (don't rewrite upstream doc), though also do not leave users to hunt around Istio. This path should be validated by someone who is less experienced with Istio (but familiar with Kubernetes).

My notes from walking through the above are documented here: https://docs.google.com/document/d/1eL7wFLUAOnPNpYMOKd3NVlLhLHEHuh4b1QkroGgV3Tc/edit?usp=sharing

Note the product compliment of this issue is: https://issues.redhat.com/browse/OSSM-3942