Improve ship damage / destruction animation

[historic_bruno]

Our ship death animation is quite lacking, even compared to older games like Empire Earth, see ​this video. Currently our ships drop straight down and through the ground when destroyed, the same behavior as structures. It would be more dramatic if instead they listed to one side and slowly sank with other nice eye candy (waves, splashes, whirlpools, bubbles), and instead of instantly disappearing, they could sink to the bottom of the water and remain there, sinking into the mud, perhaps faster than our normal unit corpses so they don't visually interfere.

Similarly to #131 for structures, there should be damage effects like smoke/fire particles for ships.