test: Add test for tycho encoder

Rename RouterEncoder to TychoEncoder

--- don't change below this line ---
ENG-4081 Took 21 minutes

src/encoding/tycho_encoder.rs

@@ -0,0 +1,13 @@
+use crate::encoding::{
+    errors::EncodingError,
+    models::{Solution, Transaction},
+    strategy_encoder::StrategySelector,
+};
+
+#[allow(dead_code)]
+pub trait TychoEncoder<S: StrategySelector> {
+    fn encode_router_calldata(
+        &self,
+        solutions: Vec<Solution>,
+    ) -> Result<Vec<Transaction>, EncodingError>;
+}