Add inventory image animation API (#16538)

builtin/game/features.lua

@@ -52,6 +52,7 @@ core.features = {
 	particlespawner_exclude_player = true,
 	generate_decorations_biomes = true,
 	chunksize_vector = true,
+	item_inventory_image_animation = true,
 }
 
 function core.has_feature(arg)

builtin/game/misc_s.lua

@@ -132,6 +132,7 @@ core.protocol_versions = {
 	["5.12.0"] = 48,
 	["5.13.0"] = 49,
 	["5.14.0"] = 50,
+	["5.15.0"] = 51,
 }
 
 setmetatable(core.protocol_versions, {__newindex = function()