CLN: Remove the Panel4D and PanelND classes

[gfyoung]

Deprecated back in v0.19.0

xref #13147

[codecov]

Codecov Report

Merging #19059 into master will decrease coverage by 0.06%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #19059      +/-   ##
==========================================
- Coverage   91.56%    91.5%   -0.07%     
==========================================
  Files         150      148       -2     
  Lines       48942    48852      -90     
==========================================
- Hits        44816    44701     -115     
- Misses       4126     4151      +25

Flag	Coverage Δ
#multiple	89.87% <100%> (-0.06%)	⬇️
#single	41.64% <66.66%> (-0.11%)	⬇️

Impacted Files	Coverage Δ
pandas/core/panel.py	96.84% <ø> (-0.01%)	⬇️
pandas/util/testing.py	84.45% <ø> (-0.3%)	⬇️
pandas/core/api.py	100% <ø> (ø)	⬆️
pandas/core/generic.py	95.9% <100%> (-0.05%)	⬇️
pandas/core/dtypes/generic.py	100% <100%> (ø)	⬆️
pandas/io/pytables.py	92.45% <100%> (-0.4%)	⬇️
pandas/plotting/_converter.py	65.22% <0%> (-1.74%)	⬇️
pandas/core/indexing.py	92.62% <0%> (-0.19%)	⬇️
... and 1 more

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[jreback]

love it! thanks! (and am NOT sad that you blew away a lot of my original code), lol.

[gfyoung]

@jreback : If you have any emotional attachment to that code, I'd be more than happy to create a separate branch where it lives on 😄

[jreback]

hahah
i still prob have the original branch
i don’t usually delete them (so i have thousands :)

[gfyoung]

i still prob have the original branch
i don’t usually delete them (so i have thousands :)

Awesome, glad we resolved that (non-)issue :)