Adds stubs for "seize" and "slash"

Author: vzotova

contracts/staking/IStaking.sol

@@ -131,6 +131,23 @@ interface IStaking {
     function withdrawNotificationReward(address recipient, uint96 amount)
         external;
 
+    /// @notice Adds staking providers to the slashing queue along with the
+    ///         amount that should be slashed from each one of them. Can only be
+    ///         called by application authorized for all staking providers in
+    ///         the array.
+    function slash(uint96 amount, address[] memory stakingProviders) external;
+
+    /// @notice Adds staking providers to the slashing queue along with the
+    ///         amount. The notifier will receive reward per each staking
+    ///         provider from notifiers treasury. Can only be called by
+    ///         application authorized for all staking providers in the array.
+    function seize(
+        uint96 amount,
+        uint256 rewardMultipier,
+        address notifier,
+        address[] memory stakingProviders
+    ) external;
+
     //
     //
     // Auxiliary functions

contracts/staking/TokenStaking.sol

@@ -174,6 +174,12 @@ contract TokenStaking is Initializable, IStaking, Checkpoints {
         uint256 tAmount
     );
     event GovernanceTransferred(address oldGovernance, address newGovernance);
+    event NotificationReceived(
+        uint96 amount,
+        uint256 rewardMultipier,
+        address notifier,
+        address[] stakingProviders
+    );
 
     modifier onlyGovernance() {
         require(governance == msg.sender, "Caller is not the governance");
@@ -506,6 +512,29 @@ contract TokenStaking is Initializable, IStaking, Checkpoints {
         token.safeTransfer(recipient, amount);
     }
 
+    /// @notice Stub for legacy "slash" method
+    function slash(uint96 amount, address[] memory _stakingProviders)
+        external
+        override
+    {
+        emit NotificationReceived(amount, 0, address(0), _stakingProviders);
+    }
+
+    /// @notice Stub for legacy "seize" method
+    function seize(
+        uint96 amount,
+        uint256 rewardMultiplier,
+        address notifier,
+        address[] memory _stakingProviders
+    ) external override {
+        emit NotificationReceived(
+            amount,
+            rewardMultiplier,
+            notifier,
+            _stakingProviders
+        );
+    }
+
     /// @notice Delegate voting power from the stake associated to the
     ///         `stakingProvider` to a `delegatee` address. Caller must be the
     ///         owner of this stake.