fix: Handle webgl context lost + Recover from hidpi scale too large

[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)

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

This PR addresses some issues with webgl contexts

• Fixed issue when WebGL context lost occurs where there was no friendly output to the user
• Fixed issue where HiDPI scaling could accidentally scale past the 4k mobile limit, if the context would scale too large it will now attempt to recover by backing off.
• Added way to add custom WebGL context lost/recovered handlers for your game

  const game = new ex.Engine({
    handleContextLost: (e) => {...},
    handleContextRestored: (e) => {...}
  })

Default context lost screen

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