feat: Experimental support for encryption using libcrux

Libcrux is a library for formally verified implementations of
cryptographic primitives. It uses multiple back ends; one of which is
libjade. A cryptographic library written in the jasmin assembly
language for high assurance cryptographic implementations.

To use compile with the experiment_libcrux feature enabled:

    cargo build --features experiment_libcrux

rosenpass/Cargo.toml

@@ -53,4 +53,5 @@ procspawn = {workspace = true}
 
 [features]
 enable_broker_api = ["rosenpass-wireguard-broker/enable_broker_api"]
-enable_memfd_alloc = []
+enable_memfd_alloc = []
+experiment_libcrux = ["rosenpass-ciphers/experiment_libcrux"]