Add OpenSSL 3 feature support to CI and configuration

[masa-koz]

Description

This pull request introduces support for the openssl3 feature across multiple files. The most important changes include updates to the workflow configuration, the feature list in Cargo.toml, and the build script to accommodate the new feature.

Support for openssl3 feature:

• .github/workflows/cargo.yml: Added --features openssl3 and --features openssl3,static to the matrix of features.
• Cargo.toml: Added openssl3 to the list of features.
• scripts/build.rs: Updated the build script to define QUIC_TLS as openssl3 when the openssl3 feature is enabled.

Testing

• cargo test --features openssl3
• cargo test --features openssl3,static

Documentation

TBD

[nibanks]

Since openssl3 is a separate submodule, we need to update include paths above.

[nibanks]

This makes me think we need automation to validate all this stuff. I wonder if we should add a prereq step to our GitHub action that fake publishes the crate locally, then uploads it. Then all other jobs work off the crate, not a git clone.