Add dw_extrapolator.py

[andrewc28]

This is an updated version of the double-Wilson Extrapolator that allows for parallel processing and handling of datasets for multiple common scaling+merging softwares.

[andrewc28]

@hkwang could you review this pull request

[DHekstra]

@andrewc28,

• could you replace the current function mean_intensity_by_resolution() with a call to reciprocalspaceship's equivalent function in scale_merged_intensities.py?
• can you refactor main() so it just calls a function extrapolate_dw() that can also be imported by external routines (e.g. by X8)?

[DHekstra]

it just occurred to me that this is probably not the most recent version of the extrapolator since handling of the intensities does not seem to be described! I was editing the manuscript and going to add how we create normalized structure factor amplitudes.

[hkwang]

Hopefully we can resolve the merge conflicts later.

To reply to Doeke's point ii about refactoring main, extrapolate.py main() can be rewritten to look like this file:
https://github.com/rs-station/rs-booster/blob/main/rsbooster/stats/ccanom.py

[DHekstra]

yes, like that!

[andrewc28]

@hkwang @DHekstra, the updated dw_extrapolator.py script has the followings edits addressed:

• Replaced the local function mean_intensity_by_resolution() with a call to reciprocalspaceship's equivalent function in scale_merged_intensities.py
• Refactored main() so the default just calls a function extrapolate_dw()
• Added NLL calculations that are outputted along with the extrapolated .mtz
• Added a -default_scan flag that performs a 1D scan over p, holding r = 0.9