Ports: Add a ClassiCube port

[cflip]

This adds a port of ClassiCube, a clone of Minecraft classic.

[gmta]

@cflip

As stated in #ports on Discord, I don't think mouse grabbing/capturing is possible without some additional kernel level features to toggle the virtualized mouse's behavior.

Maybe you can add a launcher for ClassiCube as well? Look at some other ports that have launchers for an example of how to do this in package.sh.

[cflip]

I tried adding a script to launch ClassiCube in the correct working directory, but it looks like it can't initialize the GUI when run through the launcher this way. package.sh is a bit messy at the moment, but I'll look into adding support to LibDesktop/AppFile to launch a program with a specific working directory.

[UnknownShadow200]

glGetInteger(GL_MAX_TEXTURE_SIZE) always returns 4096 https://github.com/SerenityOS/serenity/blob/6dcc808994d14de3134a6fa406a118f0100a7980/Userland/Libraries/LibGL/ContextParameter.cpp#L82, which is why it tries to make a texture atlas that tall

[cflip]

Now that sound is working, I think this is ready to go.