Linux build added
While I develop and run the game almost exclusively on Linux I have not provided a precompiled version so far. That has changed now. After having experimented with Docker and reading the itch.io package guide. I have now decided to try to provide a precompiled Linux version. I have tested it on old versions of Ubuntu, Debian and Fedora but not versions that have reached end-of-life. I have skipped out on CentOS. While the source is still the safest option this should give an easier alternative.