feat: add licensing info, natspec

Author: QEDK

LICENSE

@@ -186,7 +186,7 @@
       same "printed page" as the copyright notice for easier
       identification within third-party archives.
 
-   Copyright [yyyy] [name of copyright owner]
+   Copyright 2023 Avail Project
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.

src/MessageReceiver.sol

@@ -3,6 +3,12 @@ pragma solidity ^0.8.23;
 
 import {IMessageReceiver} from "src/interfaces/IMessageReceiver.sol";
 
+/**
+ * @author  @QEDK (Avail)
+ * @title   MessageReceiver
+ * @notice  A message receiver implementation for receiving messages from the Avail AMB
+ * @custom:security [email protected]
+ */
 abstract contract MessageReceiver is IMessageReceiver {
     address public availBridge;
 

src/WrappedAvail.sol

@@ -4,6 +4,12 @@ pragma solidity ^0.8.23;
 import {ERC20, ERC20Permit} from "lib/openzeppelin-contracts/contracts/token/ERC20/extensions/ERC20Permit.sol";
 import {IWrappedAvail} from "src/interfaces/IWrappedAvail.sol";
 
+/**
+ * @author  @QEDK (Avail)
+ * @title   WrappedAvail
+ * @notice  An Avail token implementation for Ethereum
+ * @custom:security [email protected]
+ */
 contract WrappedAvail is ERC20Permit, IWrappedAvail {
     address public immutable bridge;
 

src/lib/Merkle.sol

@@ -2,6 +2,12 @@
 // Modified from https://github.com/QEDK/solidity-misc/blob/master/contracts/Merkle.sol
 pragma solidity ^0.8.23;
 
+/**
+ * @author  @QEDK
+ * @title   Merkle
+ * @notice  A gas-efficient ordered Merkle proof of inclusion implementation
+ * @custom:security [email protected]
+ */
 library Merkle {
     function verify(bytes32[] calldata proof, bytes32 root, uint256 index, bytes32 leaf)
         internal