Add A Howto Page About Concurrency in Python

It would help to have a place where the various approaches to concurrency in Python are explained and compared. It would be especially useful to enumerate the most common concurrency-oriented workloads and show how to implement them using the different concurrency models.

I expect we would cover the following concurrency models:

• threads (threading and concurrent.futures)
• multi-processing (multiprocessing and concurrent.futures)
• async/await
• CSP/actor model (PEP 734 interpreters)
• distributed (e.g. SMP/dask)

Other related resources:

• https://github.com/faster-cpython/ideas/wiki/Tables:-Workloads
• https://github.com/faster-cpython/ideas/wiki/All-About-Python-Benchmarking
• https://github.com/ericsnowcurrently/concurrency-benchmarks

Linked PRs

• gh-123163