Add life

[zenith391]

Add basic life forms like prokaryotes and eukaryotes that would proliferate in the water. For that we need to:

• [ ] Think of a way to visualize single-celled organisms that wouldn't cause you nightmares when there are too many of those
• [ ] Think of a way for life to start (meteor?)
• [ ] Implement basic nutriments which will have different densities in the water
• [ ] Add cyanobacterias which consume CO2 + sunlight and make O2