HA Guidance

**Problem**
In the knative.dev documentation an administration section exists for knative-serving but not eventing. There should be guidence on configuring knative-eventing for HA

**[Persona:](https://github.com/knative/eventing/blob/main/docs/personas.md)**
An admin persona does not exist

**Exit Criteria**
Update docs on knative.dev

**Time Estimate (optional):**
1-3 days

**Additional context (optional)**
I noticed there is an HA section on the knative.dev website for serving. Is there an HA docs specifically for eventing or does increases replicas for components within the knative-eventing namespace apply as well?

I am rolling the Apache broker. I would be probably expect to see HA guidance for persistence brokers at this initially (In memory I wouldn't expect to be fully HA).

I would welcome an admin section in the docs under eventing just like serving.
Looking at the deployments in the knative-eventing namespace it might be useful recommending replica counts for the core and or broker specific deployments

```bash
kubectl get deploy -n knative-eventing
NAME READY UP-TO-DATE AVAILABLE AGE
eventing-controller 2/2 2 2 139m
eventing-webhook 2/2 2 2 139m
kafka-broker-dispatcher 1/1 1 1 135m
kafka-broker-receiver 1/1 1 1 135m
kafka-ch-controller 1/1 1 1 135m
kafka-ch-dispatcher 0/0 0 0 135m
kafka-controller 1/1 1 1 135m
kafka-webhook 1/1 1 1 135m
kafka-webhook-eventing 2/2 2 2 135m
```

Start with the existing knative.dev Serving HA administration section and the Eventing documentation structure. Use the listed kubectl deployment output and Apache broker context to determine which Eventing components and persistence brokers need guidance. Done means knative.dev contains an Eventing admin section with documented HA configuration and replica recommendations where supported.

Written by the indexing model from the issue text.