API: Styler.hide_columns replaced by .hide_values which also operates row-wise

[attack68]

For showing and hiding columns/rows Styler currently has two methods:

• .hide_columns(subset): which hides a selection of columns and the associated data values.
• .hide_index(): which hides the index keys completely and displays all the data values.

This PR adds a .hide_values(subset, axis, show) method, which is a superset of .hide_columns. It allows the same functionality to operate row-wise, and adds the kwarg show which allows an inverse method, exclusively showing instead of hiding.

Follow-on:

Option 1

Keep .hide_values(subset, axis, show) as is and deprecate .hide_columns.

Option 2

Make ._hide_values(subset, axis, show) a private module and include/add the public methods:

- `hide_columns`      = `_hide_values(subset=subset, axis="columns", show=False)`.
- `hide_rows`         = `_hide_values(subset=subset, axis="index", show=False)`.
- `show_columns`      = `_hide_values(subset=subset, axis="columns", show=True)`.
- `show_rows`         = `_hide_values(subset=subset, axis="index", show=True)`.

[jreback]

i find this a very confusing name, hide_axis is more appropriate

[attack68]

The trick is to distinguish between the cases of:

a) hiding select rows or columns of data (whilst other index keys or column headers are visible),
b) or displaying the data values but just hiding the index or column headers row in their entirety.

Currently hide_columns does a) whilst hide_index does b). The complete idea was that:

i) hide_values would do a) for either the index or columns axes.
ii) hide_headers (a new method) would do b) for either the index or columns axes.

?

[attack68]

@jreback i created an alternative in #41266 which seeks to achieve the same functionality in a different way re-using exiting methods and kwargs. Close this PR if you prefer the alternative,

[jreback]

i wouldn't make this user visible instead prefer hide_index, hide_columns (this can be the impl)

[attack68]

closing this is favour of #41266 for now.