Add a relay mechanism in the governor (#2926)

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

contracts/governance/Governor.sol

@@ -347,6 +347,20 @@ abstract contract Governor is Context, ERC165, EIP712, IGovernor {
         return weight;
     }
 
+    /**
+     * @dev Relays a transaction or function call to an arbitrary target. In cases where the governance executor
+     * is some contract other than the governor itself, like when using a timelock, this function can be invoked
+     * in a governance proposal to recover tokens or Ether that was sent to the governor contract by mistake.
+     * Note that if the executor is simply the governor itself, use of `relay` is redundant.
+     */
+    function relay(
+        address target,
+        uint256 value,
+        bytes calldata data
+    ) external onlyGovernance {
+        Address.functionCallWithValue(target, data, value);
+    }
+
     /**
      * @dev Address through which the governor executes action. Will be overloaded by module that execute actions
      * through another contract such as a timelock.