Describe cloudevents target endpoint

[sebgoa]

We should be able to see the endpoint for a given cloudevent target.

Right now we do not

Target                       Kind                  Status
foobar-cloudeventstarget     cloudeventstarget     online(http://localhost:63535)

[jmcx]

Atlernative idea that would be more feasible:

tmctl [describe|dump|get] target mycloudeventstarget
=> this could output a subset of the dump