add methods used in Norman & Poisot (2025)

[gottacatchenall]

• Local Pivotal Method done in Adding more samplers, utilities #76
• Spatially Correlated Poisson Sampling and w/ auxillary variables done in Adding more samplers, utilities #76
• Halton Iterative Partitioning (should be an easy extension of BAS) it is not an easy extension of BAS :(
• Dynamic Assignment Sampling (no existing implementation)