[Ethereum] Is it possible to create new wallet account in Solidity contract

Unfortunately, I cannot comment on flygoing's answer, but here's a few things to notice:

1. Withdraw old tokens balance by calling oldToken.trasnferFrom. Consider burning oldTokens, if appropriate, or send it to address(this). It'll allow you to perform double checks and ensure correctness.

2. After exchanging oldToken consider checking changes of "before" and "after" balances. Do not blindly trust oldToken.trasnferFrom return value, check oldToken.balanceOf explicitly.

If you want to make a contract which simply forwards any ETH to the contract owner, you will need to:

• Define an owner of the contract on contract creation
• Create a payable function on the contract
• Have that payable function forward the funds to that owner

Here is a really simple sample to get started (untested and not ready for production):

pragma solidity 0.4.24;

contract EthForward {
    address _owner;

    constructor() public {
        _owner = msg.sender;
    }

    function() public payable {
        _owner.transfer(msg.value);
    }
}

This contract takes advantage of two key concepts:

1. The constructor function
2. The fallback function

You should spend time learning more about solidity through official documentation and tutorials like Cryptozombies