Add instructions how to build for Ubuntu

[martincerven]

Add insctruction how to run on modern Ubuntu (22.04), something like:

git clone --recursive https://github.com/Jaysmito101/TerraForge3D.git
mkdir build && cd build
cmake ..
make 

and to run:

./terraforge3d

Also there is no Data directory, and app segfaults after running?

[Jaysmito101]

Which branch are you using? Data directory should be there in the Top level directory of the repo inside binaries

As for the segfaults, I did get some reports but sadly could not yet reproduce that? Can you give me any details? (alothough if you dont place the data directory with he exe it will segfault not being able to load resources)