Four-section clouds

In this update I'm replacing original clouds that hang from above with four-section clouds. Hanging clouds were difficult to manage and change colors properly since they were layered on top of each other. With independent clouds, color and opacity is now applied to each cloud individually depending on weather and time of day. Clouds are generated semi-randomly based on merging of four circles of different sizes, and the speed of the clouds is proportional to the wind speed:

Independent clouds also allow for more precise control over cloudy weather conditions. With the previous hanging clouds, I would move them down to cover a larger part of the sun. In contrast, with independent clouds, managing cloudy weather is more straightforward — I can adjust the number of clouds directly, making it proportional to the cloud_cover parameter provided by the weather API.