feat: Add TokenTransfer class to Curve

- This needed to be in Curve so that the executor can also take care of transfers from the user into the tycho router, to avoid having transfer actions mixed between the router and executors

src/encoding/evm/swap_encoder/swap_encoders.rs

@@ -545,6 +545,7 @@ impl SwapEncoder for CurveSwapEncoder {
             i.to_be_bytes::<1>(),
             j.to_be_bytes::<1>(),
             approval_needed,
+            (encoding_context.transfer_type as u8).to_be_bytes(),
         );
 
         Ok(args.abi_encode_packed())
@@ -1263,6 +1264,8 @@ mod tests {
                     "01",
                     // approval needed
                     "01",
+                    // transfer type
+                    "05",
                 ))
             );
         }
@@ -1329,6 +1332,8 @@ mod tests {
                     "00",
                     // approval needed
                     "01",
+                    // transfer type
+                    "05",
                 ))
             );
         }
@@ -1405,6 +1410,8 @@ mod tests {
                     "01",
                     // approval needed
                     "01",
+                    // transfer type
+                    "05",
                 ))
             );
         }