Add SponsorEverythingPaymaster contract

packages/plugins/src/paymaster/SponsorEverythingPaymaster.sol

@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.4 <0.9.0;
+
+import {IEntryPoint} from 'account-abstraction/interfaces/IEntryPoint.sol';
+
+import {BasePaymaster} from 'account-abstraction/core/BasePaymaster.sol';
+import {UserOperationLib} from 'account-abstraction/core/UserOperationLib.sol';
+import {PackedUserOperation} from 'account-abstraction/interfaces/PackedUserOperation.sol';
+
+/*//////////////////////////////////////////////////////////////////////////
+    THIS CONTRACT IS STILL IN ACTIVE DEVELOPMENT. NOT FOR PRODUCTION USE        
+//////////////////////////////////////////////////////////////////////////*/
+
+/// @title This paymaster sponsors everything.
+contract SponsorEverythingPaymaster is BasePaymaster {
+    using UserOperationLib for PackedUserOperation;
+
+    constructor(IEntryPoint _entryPoint) BasePaymaster(_entryPoint) {}
+
+    /**
+     * Validate a user operation.
+     * @param userOp     - The user operation.
+     * @param userOpHash - The hash of the user operation.
+     * @param maxCost    - The maximum cost of the user operation.
+     */
+    function _validatePaymasterUserOp(
+        PackedUserOperation calldata userOp,
+        bytes32 userOpHash,
+        uint256 maxCost
+    ) internal virtual override returns (bytes memory context, uint256 validationData) {
+        // Validation logic comes here.
+    }
+}