Feature-request: Simplify control plane with a consolidated deployment

## Describe the feature

Istio long ago evaluated their deployment strategy and they switched to a [more consolidated model](https://istio.io/latest/blog/2020/istiod).

Right now we have a number of components that are installed by default and could be merged into one.

For example:
- domain-mapping
- domainmapping-webhook
- net-*-controller
- net-istio-webhook
- webhook
- controller
- autoscaler

With a consolidated model we get some immediate benefits:
- closer to edge support (https://github.com/knative/serving/issues/13843)
- improved resource utilization due to cache sharing (https://github.com/knative/serving/issues/13843). Smaller footprint for
people who use Serving as a Serverless layer (eg. KServe), looks more appealing in general.
- easier configuration/maintenance
- faster startup

cc @ReToCode @dprotaso @rhuss @evankanderson @psschwei @nak3