Create Client Launcher

[exectails]

As launching the game is not as straightforward as just clicking the executable, it might be a good idea to create a launcher application that can make the necessary modifications to the client.xml and start the client for the user, reverting any changes it made afterwards. Our packet proxy Zemyna essentially does this as well, but its purpose is different and it's not as straightforward as it could be either.

The launcher should be simple to use for less experienced users, while supporting potentially more advanced applications, such as starting Zemyna instead of the client or applying patch files from the target server.

Since this application isn't going to be part of the core, it would probably make sense to create a dedicated project/repo for it.