feat: Add arbitrary non-convex polygon support

[eonarheim]

===:clipboard: PR Checklist :clipboard:===

• 📌 issue exists in github for these changes
• 🔬 existing tests still pass
• 🙈 code conforms to the style guide
• 📐 new tests written and passing / old tests updated with new scenario(s)
• 📄 changelog entry added (or not needed)

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This PR adds arbitrary non-convex polygon support using the ex.PolygonCollider(...).triangulate() method which produces a new ex.CompositeCollider composed of triangles.

This PR also adds a tessellate() which will produce a triangle fan ex.CompositeCollider