change peer_handler.rs to use modular handshake and encryption handler, and only expose old peer_channel_encryptor.rs to fuzz tests

Author: arik-so

lightning/src/ln/mod.rs

@@ -20,8 +20,6 @@ pub mod features;
 
 #[cfg(feature = "fuzztarget")]
 pub mod peer_channel_encryptor;
-#[cfg(not(feature = "fuzztarget"))]
-pub(crate) mod peer_channel_encryptor;
 
 mod channel;
 mod onion_utils;