Added true 3D version

[PrathameshPawar119]

1. Most of palletized containers do not use space optimization as most of pallets are of same size and type in practical use
2. Container load optimization is mostly used in non-palletized stacking, where objects can be put on each other.

Changes I did -

1. Instead of pallet input, added input of boxes with parameters as (Height, Width, Length)
2. Provided stacking on top of each other
3. Only update when click on update, instead of updating on every input change (to optimize resources)
4. If box packing is not possible, return error
5. Faster execution of solver function

Demo video -
https://drive.google.com/file/d/1mvPZJLfrj6KrMIFaOdFCBb77-E3VqFKh/view?usp=sharing