chore: create a MockSeaport contract to allow core-sdk e2e test

contracts/mock/MockSeaport.sol

@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.9;
+
+enum ItemType {
+    NATIVE,
+    ERC20,
+    ERC721,
+    ERC1155,
+    ERC721_WITH_CRITERIA,
+    ERC1155_WITH_CRITERIA
+}
+
+enum OrderType {
+    FULL_OPEN,
+    PARTIAL_OPEN,
+    FULL_RESTRICTED,
+    PARTIAL_RESTRICTED,
+    CONTRACT
+}
+
+struct OfferItem {
+    ItemType itemType;
+    address token;
+    uint256 identifierOrCriteria;
+    uint256 startAmount;
+    uint256 endAmount;
+}
+
+struct ConsiderationItem {
+    ItemType itemType;
+    address token;
+    uint256 identifierOrCriteria;
+    uint256 startAmount;
+    uint256 endAmount;
+    address payable recipient;
+}
+
+struct OrderParameters {
+    address offerer; // 0x00
+    address zone; // 0x20
+    OfferItem[] offer; // 0x40
+    ConsiderationItem[] consideration; // 0x60
+    OrderType orderType; // 0x80
+    uint256 startTime; // 0xa0
+    uint256 endTime; // 0xc0
+    bytes32 zoneHash; // 0xe0
+    uint256 salt; // 0x100
+    bytes32 conduitKey; // 0x120
+    uint256 totalOriginalConsiderationItems; // 0x140
+    // offer.length                          // 0x160
+}
+
+struct Order {
+    OrderParameters parameters;
+    bytes signature;
+}
+
+contract MockSeaport {
+    function validate(Order[] calldata orders) external returns (bool validated) {
+        return true;
+    }
+}