Animated Tilesets for All-Stars Resource Packs

This PR adds animated tilesets! I spent the day working on these, and it wasn't easy. This is primarily to help animate the All-Stars' grass tiles. You should be able to animate the other tilesets as well, but I haven't tested them.

JSONs are provided in the assets for Conveyer Belts and Liquids. There's two ways to animate the tilesets. The first is by the traditional way as used by `AnimatedSprite2D`, and the other is by how Godot animates tilesets normally as seen with the conveyer belts and liquids.

The last thing is that while doing this, I actually managed to fix the Resource Pack bug where reloading also reloads the blocks! It was surprisingly straightforward. I just edited the `BlockClass.gd` file to erase the cells when a block is hit or destroyed.

Let me know if you have any suggestions for things I should change or fix.

Scripts/Classes/Blocks/BlockClass.gd

@@ -85,6 +85,8 @@ func spawn_empty_block() -> void:
 	add_sibling(block)
 	if get_parent().get_parent() is TrackRider:
 		get_parent().get_parent().attached_entity = block
+	if get_parent() is TileMapLayer:
+		get_parent().erase_cell(get_parent().local_to_map(position))
 	block_emptied.emit()
 	queue_free()
 
@@ -95,4 +97,6 @@ func destroy() -> void:
 	var particles = destruction_particle_scene.instantiate()
 	particles.global_position = global_position
 	add_sibling(particles)
+	if get_parent() is TileMapLayer:
+		get_parent().erase_cell(get_parent().local_to_map(position))
 	queue_free()