Constructors and contract creation (#11)

Implement constructor logic and support create/create2 in the mock runtime

Signed-off-by: xermicus <cyrill@parity.io>

crates/integration/contracts/Create.sol

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.24;
+
+contract CreateA {
+    address creator;
+
+    constructor() payable {
+        creator = msg.sender;
+    }
+}
+
+contract CreateB {
+    receive() external payable {
+        new CreateA{value: msg.value}();
+    }
+
+    fallback() external {
+        new CreateA{salt: hex"01"}();
+    }
+}