add option to serialize all vtkDataset arrays

[xavArtley]

A vtk dataset can contain several data arrays but only one is used to color the mesh, the "active scalars".
Until now only this array was serialized, it allow to minimize the size of the serialized scene.
However by allowing the serialization of all data arrays and using some custom javascript functions we could make some temporal 3d visualization easier.
This PR add a parameter serialize_all_data_arrays to allow this
Here is a comparison between both options:

[codecov]

Codecov Report

Merging #1596 into master will decrease coverage by 0.34%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1596      +/-   ##
==========================================
- Coverage   85.68%   85.34%   -0.35%     
==========================================
  Files         147      147              
  Lines       16460    16705     +245     
==========================================
+ Hits        14104    14257     +153     
- Misses       2356     2448      +92     

Impacted Files	Coverage Δ
panel/pane/vtk/synchronizable_serializer.py	80.84% <ø> (-3.87%)	⬇️
panel/pane/vtk/vtk.py	94.19% <ø> (+0.01%)	⬆️
setup.py	0.00% <0.00%> (ø)
panel/auth.py	38.99% <0.00%> (+4.75%)	⬆️
panel/io/server.py	74.57% <0.00%> (+8.06%)	⬆️

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[philippjfr]

Keep this?

[xavArtley]

Yes we can keep this if vtkjs is going to support backface color we won't have to rethink about it

[philippjfr]

Apart from a few comments this looks fine to me. However I do worry about continuing to expand the custom serializer so just checking where are we on using the native vtk serializer?

[xavArtley]

Apart from a few comments this looks fine to me. However I do worry about continuing to expand the custom serializer so just checking where are we on using the native vtk serializer?

using the function VTK.import_scene , we could use any serializer which create a file wich can be read in https://kitware.github.io/vtk-js/examples/SynchronizableRenderWindow.html
actually not since we reuse panel serializer in all cases

[philippjfr]

Okay, merging for now.