Change istio-auth enabled or not to installation (istio#8632)

Currently many bug reports start out with a question from the triager
"how did you install Istio"?  Cover the auth case with this question,
as well as gather required information up front to better triage
incoming bug reports.

.github/ISSUE_TEMPLATE/bug_report.md

@@ -16,8 +16,8 @@ about: Report a bug to help us improve Istio
 **Version**
 {{ What version of Istio and Kubernetes are you using? Use `istioctl version` and `kubectl version` }}
 
-**Is Istio Auth enabled or not?**
-{{ Did you install the stable istio.yaml, istio-auth.yaml.... or if using the Helm chart please provide full command line input }}
+**Installation**
+{{ Please describe how Istio was installed }}
 
 **Environment**
 {{ Which environment, cloud vendor, OS, etc are you using? }}