Discussion regarding utility scale example for Build repetition codes tutorial

[beckykd]

Continuing the discussion from #1137 so it doesn't get lost. I think it's reasonable to NOT have a scaled-up example, but wanted the sign-off from @javabster since it was her question.

From @javabster : Do you think it's possible to add a scale-up section to the end of this notebook, to show how this could be applied in a utility scale experiment

From @ihincks : My take on this is that it's not crucial to demonstrate utlity scale for QEC examples because that hasn't be the focus of IBM utility-scale experiments to date: they have all been about things like trotterized Hamiltonian simulations with mitigation.

If this direction is mandatory, the repetition code could be kept, but repeated to more than three qubits. The routing would get quite a bit more complicated. But also, there would be a tonne of conditional if statements which are quite slow especially when done serially, and degrade the quality of the experiment. However, pushing this strategy too far would make the example feel contrived, and the results would not be great, I expect.