Add large cactus seedling

Alter 'large cactus' schematic to place another force-placed cactus node,
to replace the cactus seedling on growth.
Make schematic 5x7x5 to solve rotation, placement and protection check
issues.
Add a y-slice probability for height variation.

Growth time is tuned to not make this a faster way to obtain cactus nodes
compared to normal cactus farming.
Seedling texture by Extex101.

Use sapling/seedling description in protection intersection message in
'sapling_on_place' function.

mods/default/crafting.lua

@@ -779,6 +779,15 @@ minetest.register_craft({
 	}
 })
 
+minetest.register_craft({
+	output = "default:large_cactus_seedling",
+	recipe = {
+		{"", "default:cactus", ""},
+		{"default:cactus", "default:cactus", "default:cactus"},
+		{"", "default:cactus", ""},
+	}
+})
+
 
 --
 -- Crafting (tool repair)
@@ -1095,6 +1104,12 @@ minetest.register_craft({
 	burntime = 15,
 })
 
+minetest.register_craft({
+	type = "fuel",
+	recipe = "default:large_cactus_seedling",
+	burntime = 5,
+})
+
 minetest.register_craft({
 	type = "fuel",
 	recipe = "default:papyrus",