examples: Should hoist Anzu saucer example

[EricCousineau-TRI]

@sloretz's saucer example in Anzu PR 9565 (systems_framework_visualization_demo.cc) is great, and should be hoisted, per discussion btw @ToffeeAlbina-TRI and @IanTheEngineer.

Ideally, we make it easy to still build the example inside Anzu itself, but the code should reside in this repo.

\cc @adeeb10abbas