Add sampling overhead table and expand/update cutting explanation (#342)

* Add sampling overhead table

* typos

* Fix heading level

* Rearrange table

* Fix some Sphinx cross references

* Fix Sphinx LaTeX expressions

* Add link to IBM blog post on LOCC cutting

* Tweaks to intro

* Lots of progress

* Update docs/circuit_cutting/explanation/index.rst

Co-authored-by: Ibrahim Shehzad <[email protected]>

* Rephrase LOCC vs dynamic circuits

following discussion at
#342 (comment)

* Removed `PauliList` limitation, lifted by #523

Follow up to
#342 (comment)

* Rephrase circuit cutting intro

#342 (comment)

* Remove circuit cutting graph

It's actually very similar to the one at the top of the explanation

#342 (comment)

* Update docs/circuit_cutting/explanation/index.rst

Co-authored-by: Ibrahim Shehzad <[email protected]>

* Update docs/circuit_cutting/explanation/index.rst

Co-authored-by: Ibrahim Shehzad <[email protected]>

---------

Co-authored-by: Ibrahim Shehzad <[email protected]>
(cherry picked from commit 299c849)

# Conflicts:
#	test/cutting/qpd/test_qpd.py