make_ssl_certs: run at build time, update reference test data automatically

Bug report

Bug description:

As discussed here:
https://github.com/python/cpython/pull/107594

make_ssl_certs.py has a few shortcomings. In particular:

• it generates certificates, but does not update reference data in tests that use them, instead asking the user to copy paste the data by hand (expiration dates and serial numbers in particular)
• it is supposed to be run by hand and isn't executed in builds, which means its output has to be checked into git, cluttering the source tree, and complicating reviews of pull requests that change that output.
• expiration dates are hardcoded into the tool and can't be passed in as parameters

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-119401

Commencez par lire make_ssl_certs.py et la PR associée gh-119401, puis examinez les données de test de référence qui utilisent ses certificats. Le travail est terminé lorsque la génération des certificats s’exécute pendant les builds, met automatiquement à jour les données de référence et accepte des dates d’expiration comme paramètres sans nécessiter de sortie générée enregistrée dans le dépôt.