Add HTTP PQC Example for Java 21

[JiriOndrusek]

fixes apache/camel-quarkus#8648

Add HTTP PQC example for Java 21

Demonstrates Post-Quantum Cryptography (PQC) using Java 21's built-in support for
hybrid key exchange (X25519MLKEM768) with BouncyCastle JSSE provider.

Key features:

• TLS 1.3 with PQC hybrid key exchange using BouncyCastle JSSE
• RSA certificates compatible with standard tools (curl, OpenSSL)
• Works in JVM, native, and dev modes
• Two test profiles: PQC-only and PQC-with-fallback

Implementation notes:

• Certificates auto-generated at startup if missing
• BouncyCastle providers registered differently for JVM vs native modes
• PKCS12 keystores use SUN provider for maximum compatibility
• Build-time warnings from BouncyCastle's constraint parser are harmless (known
  limitation - see "Ignoring unsupported entry" in DisabledAlgorithmConstraints bcgit/bc-java#1343)

[JiriOndrusek]

@oscerd May I ask your for a review from PQC perspective?

[jamesnetherton]

Correct me if I'm wrong, but I assume this can't work with our current CI setup. The baseline is JDK 17, we'd have to exclude this project from being built or something like that.