More Leaf Particles

(1.21.8)

Changes:

• The wind factor is now configurable for all particles (defaults to 10.0F). When set to 0.0F, the particle will fall straight down to the ground.
• Every particle now has an option to flow away (defaults to false). When true, the particle will gradually change its position instead of just descending to the ground in circles.
• Minor code refactorings