Flasc dataframe

[paulf81]

Add FlascDataFrame

This pull request is taking over from #199 to add a new object called a FlascDataFrame inherits from pandas.DataFrame, but will provide some extra utilities for mapping between different naming conventions and dataframe formats ("long" data, "wide" data, etc). Still a work in progress but nearing readiness so opening draft pull request.

Feature or improvement description

• Implements a new FlascDataFrame object that inherits from pandas.DataFrame but provides extra utility
• Implements methods to convert to user formats such as long or wide with alternative channel names
• Provides methods to convert to a wind-up (https://github.com/resgroup/wind-up) style frame and use import wind-up modules to conduct uplift analysis using those methods
• Updated documentation and examples

Left to do:

• [ ] Have we brought in enough capabliities, thinking especially of deprecating some of the functions in dataframe_manipulations.py that could better be FlascDataframe members
• [ ] Go through code and look to update type hints and returns where appropriate from pd.Dataframe to and/or FlascDataframe
• [ ] Update examples to use FlascDataframe
• [ ] Add a documention page for FlascDataframe and wind-up
• [ ] Review and merge using a merge commit (rather than squashing and merging)

Related issue, if one exists

Impacted areas of the software

Additional supporting information