Adding a characterization module + notebook

[majo-lozano]

Adding a module to run characterization experiments explicitly for users to update backend properties with real-time data. The experiments supported are: SPAM, Isolated 1Q RB, 2Q Layer Fidelity, T1, T2 Hahn.

The main idea of this is to have users run and update these properties with a single line, so they can quickly call this code on their own notebooks.

[majo-lozano]

Adding @abbycross to the loop. This is the PR that needs to be merged before we can update the tutorial here.

I believe @dcmckayibm can approve this PR. It has been tested already.

[jyu00]

It makes more sense to run them inside a Batch, if one doesn't want to pay for the cost of a session. Batch doesn't incur additional cost, and batch jobs are run together, so you don't run into the issue of device drift between these jobs.

Of course, Session is still the best if one wants to do characterization and use that data (e.g. for transpilation) while it's still fresh.

[jyu00]

These plots are helpful, but I think it'd be even more convincing to show the results of the same circuit (e.g. a mirrored one) using reported vs measured properties.

Alternatively we can just mention this tool in this tutorial, which already does result comparison.