feat: Implement SplitSwapStrategyEncoder

The strategy works as follows:
- Manage approvals needed
- Compute min amount (if check amount is any):
  - if slippage is defined, apply slippage on the expected amount and take the min value between that and the check amount
  - if not, it's just the check amount
- Iterate through the swaps
  - call the corresponding swap encoder to encode the swap
  - add swap header (tokens indexes and split)
  - ple encode the swaps
- Add extra inputs (amounts, token addresses, min amount, (un)wrap, number of tokens and receiver)

Misc:
- Move executor address and selector encoding inside the SwapEncoder
- Add default executor_selector to SwapEncoder
- Pass router address inside the SplitSwapStrategyEncoder
- Move Permit2 inside the SplitSwapStrategyEncoder. It is a responsibility and a specificity of the strategy to need permit2 approvals

--- don't change below this line ---
ENG-4081 Took 1 hour 21 minutes

src/encoding/models.rs

@@ -1,7 +1,7 @@
 use num_bigint::BigUint;
 use tycho_core::{dto::ProtocolComponent, Bytes};
 
-#[derive(Clone)]
+#[derive(Clone, Default, Debug)]
 #[allow(dead_code)]
 pub struct Solution {
     /// True if the solution is an exact output solution.
@@ -11,7 +11,7 @@ pub struct Solution {
     /// Amount of the given token.
     pub given_amount: BigUint,
     /// The token being bought (exact in) or sold (exact out).
-    checked_token: Bytes,
+    pub checked_token: Bytes,
     /// Expected amount of the bought token (exact in) or sold token (exact out).
     pub expected_amount: BigUint,
     /// Minimum amount to be checked for the solution to be valid.
@@ -35,14 +35,14 @@ pub struct Solution {
     pub native_action: Option<NativeAction>,
 }
 
-#[derive(Clone, PartialEq)]
+#[derive(Clone, PartialEq, Debug)]
 #[allow(dead_code)]
 pub enum NativeAction {
     Wrap,
     Unwrap,
 }
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 #[allow(dead_code)]
 pub struct Swap {
     /// Protocol component from tycho indexer
@@ -51,7 +51,7 @@ pub struct Swap {
     pub token_in: Bytes,
     /// Token being output from the pool.
     pub token_out: Bytes,
-    /// Fraction of the amount to be swapped in this operation.
+    /// Percentage of the amount to be swapped in this operation.
     pub split: f64,
 }