Add SVG elliptical arc support

[newell]

Changelog / Overview

Motivation

Add SVG elliptical arc support to manim.

See: https://www.w3.org/TR/SVG11/paths.html#PathDataEllipticalArcCommands

Explanation for Changes

Adds support to manim for SVGs that contain paths with elliptical arcs.

Testing Status

manim rendering https://www.w3.org/TR/SVG11/images/paths/arcs01.svg

Further Comments

Checklist

• I have read the Contributing Guidelines
• I have written a descriptive PR title (see top of PR template for examples)
• I have written a changelog entry for the PR or deem it unnecessary
• My new functions/classes either have a docstring or are private
• My new functions/classes have tests added and (optional) examples in the docs
• My new documentation builds, looks correctly formatted, and adds no additional build warnings

Reviewer Checklist

• The PR title is descriptive enough
• The PR is labeled correctly
• The changelog entry is completed if necessary
• Newly added functions/classes either have a docstring or are private
• Newly added functions/classes have tests added and (optional) examples in the docs
• Newly added documentation builds, looks correctly formatted, and adds no additional build warnings

[markromanmiller]

Overall the code is good - I saw a version of this earlier today.

The only blocking changes are the ones done by the CI - have you run black and isort?

One improvement I will suggest but not require is handing a commands with 7*n numbers, not just 7. If more than 7 numbers appear after an arc command, the next 7 are interpreted as their own arc command, and so on. While this is part of the spec, I don't expect to see it all that often, so it's not a blocking issue.

[markromanmiller]

Build looks good, but looks like I don't have edit access as a maintainer, so I can't update with the most recent version to perform the merge.

Can you either update and ping me or allow access for maintainers? (tbh not sure where that option is)