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

[kanavin]

Bug report

Bug description:

As discussed here:
#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-119400: make_ssl_certs: update reference test data automatically, pass in expiration dates as parameters #119400  #119401