Implements SpiralGroundCurve::GInverse().

[agalbachicar]

🎉 New feature

Part of #265 Goes on top of #270

Summary

Implements GInverse(). Tested against the normalized spiral. With htis PR the curve implementation is complete and validated against the normalized spiral. Future PRs will work on non-normalized spirals.

Test it

Via unit tests.

Checklist

• [x] Signed all commits for DCO
• [x] Added tests
• [ ] Added example and/or tutorial
• [ ] Updated documentation (as needed)
• [ ] Updated migration guide (as needed)
• [ ] Consider updating Python bindings (if it affects the public API)

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[agalbachicar]

Declining in favor of a new implementation.