feat: Add evm feature gate

- Move all evm code inside evm directory
- StrategyEncoder:
  - Kept StrategyEncoder trait but created a new one: EVMStrategyEncoder to implement encode_protocol_header (that is evm specific).
  - All StrategyEncoders implement both traits now
  - Renamed DefaultStrategySelector -> EVMStrategySelector
- RouterEncoder:
  - Created a RouterEncoder trait and a EVMRouterEncoder that implements it
- Moved utils inside evm directory as well
- Renamed config.json -> executor_addresses.json and moved it to a higher config directory
- Make alloy optional and dependent on the evm feature gate

--- don't change below this line ---
ENG-4075 <#DTT#>

src/encoding/swap_encoder.rs

@@ -0,0 +1,12 @@
+use anyhow::Error;
+
+use crate::encoding::models::{EncodingContext, Swap};
+
+#[allow(dead_code)]
+pub trait SwapEncoder: Sync + Send {
+    fn new(executor_address: String) -> Self
+    where
+        Self: Sized;
+    fn encode_swap(&self, swap: Swap, encoding_context: EncodingContext) -> Result<Vec<u8>, Error>;
+    fn executor_address(&self) -> &str;
+}