Feat/add openzeppelin dep

.gitmodules

@@ -7,3 +7,9 @@
 [submodule "lib/ds-test"]
 	path = lib/ds-test
 	url = https://github.com/dapphub/ds-test
+[submodule "lib/openzeppelin-contracts"]
+	path = lib/openzeppelin-contracts
+	url = https://github.com/Openzeppelin/openzeppelin-contracts
+[submodule "lib/openzeppelin-contracts-upgradeable"]
+	path = lib/openzeppelin-contracts-upgradeable
+	url = https://github.com/Openzeppelin/openzeppelin-contracts-upgradeable

remappings.txt

@@ -1,7 +1,5 @@
-@openzeppelin-upgrades/=lib/eigenlayer-contracts/lib/openzeppelin-contracts-upgradeable/
-@openzeppelin/=lib/eigenlayer-contracts/lib/openzeppelin-contracts/
+@openzeppelin-upgrades/=lib/openzeppelin-contracts-upgradeable/
+@openzeppelin/=lib/openzeppelin-contracts/
 ds-test/=lib/ds-test/src/
 eigenlayer-contracts/=lib/eigenlayer-contracts/
 forge-std/=lib/forge-std/src/
-openzeppelin-contracts-upgradeable/=lib/eigenlayer-contracts/lib/openzeppelin-contracts-upgradeable/
-openzeppelin-contracts/=lib/eigenlayer-contracts/lib/openzeppelin-contracts/

src/interfaces/IDelayedServiceManager.sol

@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: BUSL-1.1
+pragma solidity >=0.5.0;
+/**
+ * @title Interface for a middleware / service that may look at past stake amounts.
+ * @author Layr Labs, Inc.
+ * @notice Terms of Service: https://docs.eigenlayer.xyz/overview/terms-of-service
+ * @notice Specifically, this interface is designed for services that consult stake amounts up to `BLOCK_STALE_MEASURE`
+ * blocks in the past. This may be necessary due to, e.g., network processing & communication delays, or to avoid race conditions
+ * that could be present with coordinating aggregate operator signatures while service operators are registering & de-registering.
+ * @dev To clarify edge cases, the middleware can look `BLOCK_STALE_MEASURE` blocks into the past, i.e. it may trust stakes from the interval
+ * [block.number - BLOCK_STALE_MEASURE, block.number] (specifically, *inclusive* of the block that is `BLOCK_STALE_MEASURE` before the current one)
+ */
+interface IDelayedService {
+    /// @notice The maximum amount of blocks in the past that the service will consider stake amounts to still be 'valid'.
+    function BLOCK_STALE_MEASURE() external view returns (uint32);
+}