Bookworm and Ruby 3.0: Use system root CAs

What does this MR do and why?

Link the system certificate directory to the custom OpenSSL certificate directory. Fixes cert chain errors for HTTP requests sent from Ruby.

Relates #132

Relates gitlab#441409 (closed)

Test notes: !750 (comment 1768980317)

Checklist

• (If applicable) Add patches if required for upgrading Ruby version in https://gitlab.com/gitlab-org/gitlab-build-images/-/tree/master/patches/ruby.