Event Lineage/Graph View

**Problem**
Eventing provides APIs to build a loosely coupled, distributed system. This provides teams and services with high degrees of flexibility and autonomy, however it also makes the relations between services hard to understand as the number of services connected in the Event Mesh increases.
By providing a graph view of the "event lineage" we can enable users to understand their system and debug complex problems. Full proposal doc is [here](https://docs.google.com/document/d/12XIK4AYkwgkA47wjKQ2YA8WztUBGz--3W7nicIEG02E/edit?usp=sharing).

**[Persona:](https://github.com/knative/eventing/blob/main/docs/personas.md)**
Which persona is this feature for?
Administrators and developers

**Exit Criteria**
TODO

**Time Estimate (optional):**
How many developer-days do you think this may take to resolve? 30+

**Additional context (optional)**
Add any other context about the feature request here.