Add wstETH L2 token implementation (#2)

Author: nik-suri

src/interfaces/external/INTTToken.sol

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: Apache 2
+pragma solidity ^0.8.19;
+
+interface INTTToken {
+    error CallerNotMinter(address caller);
+
+    function mint(address account, uint256 amount) external;
+}

src/token/wstETHL2Token.sol

@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.19;
+
+import "openzeppelin-contracts/contracts/token/ERC20/extensions/ERC20Burnable.sol";
+import "openzeppelin-contracts/contracts/access/Ownable.sol";
+
+import "../interfaces/external/INTTToken.sol";
+
+contract wstETHL2Token is INTTToken, ERC20Burnable, Ownable {
+    address immutable _minter;
+
+    modifier onlyMinter() {
+        if (msg.sender != _minter) {
+            revert CallerNotMinter(msg.sender);
+        }
+        _;
+    }
+
+    constructor(string memory name, string memory symbol, address minter, address owner)
+        ERC20(name, symbol)
+        Ownable(owner)
+    {
+        _minter = minter;
+    }
+
+    function mint(address account, uint256 amount) external onlyMinter {
+        _mint(account, amount);
+    }
+}