Add `nest_lists` function to NestedFrame API

[dougbrn]

Feature request
I was trying to help someone with a problem like this yesterday:

import nested_pandas as npd
ndf = npd.NestedFrame({"a":[1,2,3], "b":[[1,2,3],[4,5,6],[7,8,9]], "c":[[10,20,30],[40,50,60],[70,80,90]]})

# How do I pack b and c into a nested structure?
from nested_pandas.series.packer import pack_lists
nested = pack_lists(ndf[["b", "c"]], name="nested")
# join back to df as nested col
ndf.join(nested)

While certainly doable using our packing module, I realized this is such a fundamental use case that I was surprised we don't have a top level function for it. I propose we add a top-level function, like nest_lists that would accomplish this as follows:

ndf.nest_lists(columns=["b","c"], name="nested", drop=True) #drop signals we remove b and c from base columns

Before submitting
Please check the following:

• I have described the purpose of the suggested change, specifying what I need the enhancement to accomplish, i.e. what problem it solves.
• I have included any relevant links, screenshots, environment information, and data relevant to implementing the requested feature, as well as pseudocode for how I want to access the new functionality.
• If I have ideas for how the new feature could be implemented, I have provided explanations and/or pseudocode and/or task lists for the steps.

[hombit]

Thanks, it is a good use-case. I hope it should be possible to implement it through .add_nested, without adding a new method

[hombit]

I was thinking about it, and I agree that the new method proposed would be a better option