Add a tutorial for QSE

[purva-thakre]

The landing page for each technique links to a tutorial using that technique. There is no tutorial for QSE in Examples section of the docs.

Related to #1773

1. We should replicate the results of the reference paper for QSE using mitiq.qse as a tutorial. https://arxiv.org/abs/1903.05786
2. There could also be another tutorial stacking QSE with ZNE. The docs refer to this without providing an example.

QSE related discussion that we should provide clearer instructions on how to stack QEM methods: #2267

[Tarun-Kumar07]

Hey @purva-thakre, I'm new to mitiq and would love to contribute. Can I work on this issue?

[purva-thakre]

@Tarun-Kumar07 Assigned! Feel free to start a discussion if you need help.

I think item 1 should be easier. Note that the documentation workflow diagram has an incorrect module name (#2272) and some parts of the documentation are also incomplete (#2266).

Item 2 will require #2288 and #2281 to be merged. You don't have to work on this one.

[purva-thakre]

Hi @Tarun-Kumar07 , do you need any help with this issue? Feel free to start a discussion https://github.com/unitaryfund/mitiq/discussions