Big thanks to Valeria for the pixel art: https://github.com/ValeriaGart

It just moves the existing content upwards and starts the new content from the top of the terminal.

`\e[2J` moves the viewable lines out of view.
`\e[1;1H` moves the cursor to row 1, column 1.

This will give the illusion of clearing the screen, but it's still possible to scroll up to see the previous content.

The images were then converted to characters with a tool called `px2ansi`:
https://github.com/Nellousan/px2ansi.git

When defining the `WELCOME_MSG` macro in the Makefile, it simply has to be specified wether it should be defined from the make variable `WELCOME_MSG1` or `WELCOME_MSG2`.

Also rename the previous `WELCOME_MSG` macro to `WELCOME_ART`.

Once the user has seen `Crash` once, they should be able to figure out the symbolic meaning of the wave.

This is to make the edges of the art more obvious.
Before it looked like it was cut by the window and you could scroll up to see more, which was misleading.