feat: [#1733][#1734] New FullScreen and Dynamic DisplayModes

[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)

==================

Closes #1733
Closes #1734

Changes:

• Breaking change: DisplayMode.FullScreen will now scale the game to fit the available space, preserving the aspectRatio. This matches the browser "FullScreen" api behavior
• New: DisplayMode.Dynamic now does what DisplayMode.FullScreen used to do, the resolution and viewport dynamically adjust to fit the available space, DOES NOT preserve aspectRatio
• Fix: In the the browser "FullScreen" api, coordinates are now correctly mapped from page space to world space
• Added: Screen helpers for mapping between world, screen, and page space coordinates
• Deprecate: DisplayMode.Position CSS can accomplish this task better than Excalibur
• Tests!