Update TLS certificates and use new certificates submodule

[dhalbert]

• Fixes SSL error with 8.2.2 or later when talking to github #8299

Use the new repo https://github.com/adafruit/certificates as a submodule instead of https://github.com/adafruit/nina-fw. This new repo provides a revised roots.pem that fixes the problems introduced in 8.2.2 when the nina-fw cert bundle was updated.

• The new cert repo has a manual test for a large number of URLs, as does https://github.com/arduino/nina-fw. The URL list includes a number of URLs used by Adafruit code, including from the Learn Guide repo.
• https://github.com is now accessible. The "Basic Internet Test" in many guides now works. Tested on Pico W and MatrixPortal S3.
• The NASA site test code in updating cert nina-fw#41 also works.
• The new roots.pem includes roots from Entrust and GoDaddy that were not there before Several sites needed these. But the new file is for some reason about 800 bytes smaller than the older nina-fw one: perhaps some obsolete certs are now gone.

[RetiredWizard]

I loaded this up on an ESP32-S3-devkit-n8r8 and it worked great. It seemed like the WiFi connection was faster and more reliable than I normally see. I'm not sure if that's a possible benefit of this PR or if I just had a really good session for some reason.

[jepler]

Motivation is clear, execution seems fine but didn't test.

[dhalbert]

It seemed like the WiFi connection was faster and more reliable than I normally see. I'm not sure if that's a possible benefit of this PR or if I just had a really good session for some reason.

It's just cert updates, and there are no previous PR's that should improve things. But glad it worked -- thanks for testing!