Better downselect sampler

[afontani]

Is your feature request related to a problem? Please describe.
There has been a lot of discussion on how to get specific samples that might be a very small portion of the stock. Our "resample" workflow is not ideal to create these samples. Often a single sample cannot be found in the initial 350k samples.

Describe the solution you'd like
Add a downselect sampler option that is able to natively downselect the characteristics to the desired stock cohort.

Describe alternatives you've considered
Adding this to resstock/resources/run_sampling.rb. I think it is more useful in buildstockbatch. Although similar capabilities might need to be developed for resstock/resources/run_sampling.rb.

Additional context
None.