Add invisible spice bloom spawn

When real spiceblooms explode, they spawn an invisible
spicebloom.spawnpoint actor, which only 'grows' when the cell is of
GrowthTerrainType. When 'exploding', it then displays the animation of
blowing spice up into the air, and spawns a real spicebloom.

This replicates the original behavior where spice blooms would only grow
on sand cells that had been harvested and free of spice.

mods/d2k/sequences/misc.yaml

@@ -46,6 +46,11 @@ explosion:
 		BlendMode: Alpha
 		Offset: 12, -10
 		Tick: 120
+	bloomspawn: DATA.R8
+		Start: 3980
+		Length: 8
+		Tick: 120
+		Offset: 0, -16
 	corpse: DATA.R8
 		Start: 430
 		Length: 12
@@ -328,6 +333,11 @@ crate:
 		Offset: -16,-16
 
 spicebloom:
+	grow0: DATA.R8
+		Start: 106
+		Length: 1
+		ZOffset: -1023
+		Offset: -16,-16
 	grow1: DATA.R8
 		Start: 107
 		Length: 1