Eliminate dependence on most uniswap functions

lib_sol8/v3-periphery/contracts/interfaces/external/IWETH9.sol

@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+pragma solidity =0.7.6;
+
+import '@openzeppelin/contracts/token/ERC20/IERC20.sol';
+
+/// @title Interface for WETH9
+interface IWETH9 is IERC20 {
+    /// @notice Deposit ether to get wrapped ether
+    function deposit() external payable;
+
+    /// @notice Withdraw wrapped ether to get ether
+    function withdraw(uint256) external;
+}