Add ability to export record feature data with image arrays

[d33bs]

CytoDataFrames have the ability to find and relate cropped image data with feature data. It'd be helpful to find a way to export this data to a file for use elsewhere. For example, each record / row would include all existing feature data and also new columns for cropped images arrays so they could be used elsewhere.

This might look like:

from cytodataframe import CytoDataFrame

cdf = CytoDataFrame(...)
cdf.to_lance("filename.lance")

Brought up in discussion with @cmattson