feat: Add estimated_amount_in to Swap. Add SwapBuilder

Use SwapBuilder everywhere inside crate
Integration tests will be done later

--- don't change below this line ---
ENG-4696 Took 1 hour 56 minutes

Took 4 minutes

examples/uniswapx-encoding-example/main.rs

@@ -83,6 +83,7 @@ fn main() {
         split: 0f64,
         user_data: None,
         protocol_state: None,
+        estimated_amount_in: None,
     };
     let swap_usdc_usdt = Swap {
         component: ProtocolComponent {
@@ -101,6 +102,7 @@ fn main() {
         split: 0f64,
         user_data: None,
         protocol_state: None,
+        estimated_amount_in: None,
     };
 
     // Then we create a solution object with the previous swap