[VTK] add vtkFollower

[xavArtley]

Implement and fix #1412
I had to port Kitware/vtk-js#1511 into panel vtk models because until Kitware/vtk-js#1493 is solved I can't update vtk-js version

• : tests
• : deserializer

[codecov]

Codecov Report

Merging #1451 into master will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1451      +/-   ##
==========================================
+ Coverage   87.78%   87.79%   +0.01%     
==========================================
  Files         135      135              
  Lines       14930    14946      +16     
==========================================
+ Hits        13106    13122      +16     
  Misses       1824     1824              

Impacted Files	Coverage Δ
panel/pane/vtk/synchronizable_deserializer.py	97.50% <100.00%> (ø)
panel/pane/vtk/synchronizable_serializer.py	84.70% <100.00%> (+0.23%)	⬆️
panel/tests/pane/test_vtk.py	98.23% <100.00%> (+0.06%)	⬆️

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[philippjfr]

Looks good to me! Thanks @xavArtley.

[GilShoshan94]

Looks amazing !!!
Thank you ! @xavArtley @jourdain @philippjfr