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/evm/approvals/protocol_approvals_manager.rs

@@ -0,0 +1,49 @@
+use std::{env, sync::Arc};
+
+use alloy::{
+    providers::{ProviderBuilder, RootProvider},
+    transports::BoxTransport,
+};
+use alloy_primitives::Address;
+use dotenv::dotenv;
+
+#[allow(dead_code)]
+pub struct ProtocolApprovalsManager {
+    client: Arc<RootProvider<BoxTransport>>,
+}
+impl ProtocolApprovalsManager {
+    pub fn new() -> Self {
+        Self { client: get_client() }
+    }
+    pub async fn approval_needed(
+        &self,
+        _token: Address,
+        _spender_address: Address,
+        _router_address: Address,
+    ) -> bool {
+        todo!()
+        // should be something like
+        // let allowance = self
+        //     .client
+        //     .call(token, "allowance(address,address)(uint256)", (router_address,
+        // spender_address))     .await;
+        //
+        // allowance == U256::ZERO // If allowance is 0, approval is needed
+    }
+}
+
+pub fn get_client() -> Arc<RootProvider<BoxTransport>> {
+    dotenv().ok();
+    let eth_rpc_url = env::var("ETH_RPC_URL").expect("Missing ETH_RPC_URL in environment");
+    let runtime = tokio::runtime::Handle::try_current()
+        .is_err()
+        .then(|| tokio::runtime::Runtime::new().unwrap())
+        .unwrap();
+    let client = runtime.block_on(async {
+        ProviderBuilder::new()
+            .on_builtin(&eth_rpc_url)
+            .await
+            .unwrap()
+    });
+    Arc::new(client)
+}