audit the standard library TLS implementation with respect to RFC 8446

[andrewrk]

Extracted from #13980.

Ensure the implementation is complete and compliant.

This is labeled "bug" because it is likely that performing the audit will identify bugs in the implementation.

Related:

• std.crypto.tls.Client: send an alert message to the server when an error occurs #14167
• ship root SSL certificates along with ziglang.org-vendored tarballs #14168
• std.crypto.Certificate.Bundle: find system-installed root certificates on macOS #14169
• std.crypto.Certificate.Bundle: find system-installed root certificates on Windows #14170
• add std.crypto.tls.Server #14171
• test std lib TLS implementation against many real world servers #14172
• look into TCP fastopen and TCP_QUICKACK #14173
• increase test coverage of std.crypto.tls #14174
• std.crypto.Certificate.verify: additionally verify "key usage" #14175
• make std.url / std.uri more complete and RFC-compliant #14176
• std.crypto.Certificate: wildcard certs should only validate one level of sub-domain #14177