feat: Add pixelRatio override for Text rendering

[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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Closes #2291

This PR assists in pixelated Text rendering by increasing the number of internal pixels available on the canvas, to do this I added a pixelRatio that can be set at Engine constructor time.

Before antialiasing is off (pixel art mode), default pixelRatio

After antialiasing is off (pixel art mode) but pixelRatio is set to 4

Changes:

• Added pixelRatio option to Engine constructor
• Added/updated tests
• Commented Font renderer