feat: improve export functionality

[flekschas]

This PR improves scatterplot.export() by allowing to customize the rendering settings during the export.

Description

What was changed in this pull request?

• Added antiAliasing property to allow adjusting the anti-aliasing of points
• Added pixelAligned property to allow aligning points with the pixel grid
• Enhanced export() to allow up or down scaling the exported image as well as adjusting the anti-aliasing and pixel alignment settings during export
• Exposed the renderer's resize() function in case one wants to resize the renderer's canvas.

Why is it necessary?

Fixes #175

All changes enable better exporting. E.g., during export it can be useful to upscale the image, render the points a tad smoother by increasing the anti-aliasing and snapping points to the pixel grid.

Huge thanks go to @danr for providing the necessary code changes in #175! 🙏

Checklist

• Provided a concise title as a semantic commit message (e.g. "fix: correctly handle undefined properties")
• CHANGELOG.md updated
• Tests added or updated
• Documentation in README.md added or updated
• Example(s) added or updated
• Screenshot, gif, or video attached for visual changes

[danr]

Perfect! 🎉