Port new PQC API and tests

[vietj]

The single useHybridKeyExchange is removed in favor of two properties:

• key-exchange-groups: the user can specify which key exchange groups they want to use
• pqc-enforcement-policy: the user can specify how PQC will be enforced by Vert.x. The policies are:
  • STRICT: only PQC can be used to establish secure connections. If no SSL engine supports it, application won't start. If clients don't support it, SSL handshake fails
  • CLIENT_NEGOTIATED: if no SSL engine supports PQC, application won't start. If clients don't support it, falls back to other key exchange group
  • RELAXED: no enforcement whatsoever, traditional TLS negotiation

When PQC is required (STRICT or CLIENT_NEGOTIATED), Vert.x auto-selects a PQC-capable engine (JDK or OpenSSL) if none is explicitly configured. If none is available, application fails to start with a VertxException ("PQC enforcement policy requires X25519MLKEM768 but neither JDK nor OpenSSL supports it".

The resolution of key exchange groups and PQC enforcement policy (selecting an available SSL engine, adding X25519MLKEM768 to the list of supported groups for CLIENT_NEGOTIATED or restricting the list of supported groups for STRICT) is performed once in SslContextManager.