feat: Remove slippage and expected_amount from Solution

The user is responsible for coming up with a sensible value for this themselves

Took 37 minutes

examples/encoding-example/main.rs

@@ -55,7 +55,7 @@ fn main() {
         given_amount: BigUint::from_str("1_000000000000000000").expect("Failed to create amount"),
         checked_token: usdc.clone(),
         exact_out: false, // it's an exact in solution
-        checked_amount: Some(BigUint::from(1u64)),
+        checked_amount: BigUint::from(1u64),
         swaps: vec![simple_swap],
         ..Default::default()
     };