feat: silo llama apr oracle

src/strategies/crvUSD/SiloLlamaAprOracle.sol

@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: AGPL-3.0
+pragma solidity 0.8.18;
+
+import {AprOracleBase} from "@periphery/AprOracle/AprOracleBase.sol";
+
+contract StrategyAprOracle is AprOracleBase {
+    constructor() AprOracleBase("Strategy Apr Oracle Example", msg.sender) {}
+
+    /**
+     * @notice Will return the expected Apr of a strategy post a debt change.
+     * @dev _delta is a signed integer so that it can also represent a debt
+     * decrease.
+     *
+     * This should return the annual expected return at the current timestamp
+     * represented as 1e18.
+     *
+     *      ie. 10% == 1e17
+     *
+     * _delta will be == 0 to get the current apr.
+     *
+     * This will potentially be called during non-view functions so gas
+     * efficiency should be taken into account.
+     *
+     * @param _strategy The token to get the apr for.
+     * @param _delta The difference in debt.
+     * @return . The expected apr for the strategy represented as 1e18.
+     */
+    function aprAfterDebtChange(
+        address _strategy,
+        int256 _delta
+    ) external view override returns (uint256) {
+        // TODO: Implement any necessary logic to return the most accurate
+        //      APR estimation for the strategy.
+        return 1e17;
+    }
+}