refactor(WebGL): remove support for WebGL1

[daker]

Context

Results

Changes

• Documentation and TypeScript definitions were updated to match those changes

PR and Code Checklist

• semantic-release commit messages
• Run npm run reformat to have correctly formatted code

Testing

• This change adds or fixes unit tests
• Tested environment:
  • vtk.js:
  • OS:
  • Browser:

[finetjul]

How does it compare with #2212 ?

I find it a bit misleading that claiming it remove WebGL1 support but it still render as in "WebGL1" would do, e.g. it duplicates points for each cells (see vtkCellArrayBufferObject). This is big bottleneck when it comes to rendering initialization and memory usage.

It can be done in a second pass though.

[daker]

@finetjul it's the same as #2212 but rebased. i get your point i will try to see if i can do something

[finetjul]

@Jo-Byr can you have a look at the WebGL2 implementation ?

@daker do you see an improvement of performance (TTFF)?