Add websocket handler on server, connect from client

Additionally add /test handler that triggers server->client WS message

server/src/lib.rs

@@ -4,6 +4,8 @@ pub mod graphql;
 pub mod mail;
 pub mod newsreader;
 pub mod nm;
+pub mod ws;
+
 #[cfg(feature = "tantivy")]
 pub mod tantivy;