As a user I would like to use alloy-receiver as my default trace collector instead of Tempo.

Currently there is some logic in Istio to publish traces straight to tempo or jeager. https://repo1.dso.mil/big-bang/bigbang/-/blob/master/chart/templates/istio/values.yaml?ref_type=heads#L40

1. make sure when enabling Tempo alloy-receiver is also enabled and configured to publish to Tempo as a backend
2. update Istio configurations to publish to alloy instead of tempo
3. Document tracing endpoint url that customers can use to publish traces to(could this just live in the Kiali config?)