Make workflow internal behavior into interceptor APIs

[pyricau]

Check our internal ActionLogger and WorkflowSystemTracer and create APIs so that those implementations are straightforward and show 0 knowledge of workflow internals.

Some examples:

• to get access to actions you need to wrap a render then wrap actions + wrap render child + wrap actions (all you want is "an API for knowing about actions")
• relying on "session.parent = null" for root
• tracking of the map of workflow names
• the fact that we are mirroring the skipping logic to figure out if workflow will skip a render

[steve-the-edwards]

I think this likely looks like a WorkflowTracer API that includes these.