Introduce snap-points strategy

[dy]

Reduces the number of points to draw depending on data box, so that multiple points at the same pixel are rendered as a single point.
The strategy is adapted from gl-scatter2d.
That fixes webgl memory overflow issue, but now there's array allocation limit issue due to huge number of glyph vertices.
Mixed with sprites strategy allows to avoid overrendering glyphs and enable big data rendering.

[etpinard]

Fantastic 🎉

Is this enough to fix plotly/plotly.js#566 ?

I was having issues reproducing plotly/plotly.js#566 on my laptop, so I'll test this out on different machines once you're happy with the patch.

[dy]

@etpinard this patch solves only half of the problem, specifically webgl memory overflow, but now there is js overflow due to massive number of glyph vertices. I was researching some text rendering solutions, like font-atlas for bitmap fonts etc and turned out SDF fonts are the best for that, so I am trying to get text rendering thing done with tiny-sdf, that allows to get rid of text tesselation used now, that would allow us to shrink the size of the plotly package up to 30% in the future, in theory) Stay tuned

[etpinard]

Stay tuned

Looking forward! Thanks a lot for looking into this 🍻