Enhanced Bin Packing propagator

[95A31]

Hello,

This patch implements a stronger pruning technique for the BinPacking constraint. It leverages tighter lower bounds based on Dual-Feasible Functions. This approach was presented at CP 2024 in the paper CP for Bin Packing with Multi-Core and GPUs.

There might be a need for some polishing and testing, but I think the benefits are worth the effort. I attached a simple model for testing.

Cheers

bpp.mzn.txt N2W1B2R5.dzn.txt