Tracking Issue: DPI Usability Upgrades

[Osspial]

This issue tracks the implementation of the HiDPI API changes that were discussed in #837. PRs implementing this change should be made against the dpi-overhaul branch, and we'll merge that branch onto master once it's implemented on all platforms.

• Public API changed
• Implemented on all platforms
  • Windows - WIP - Make EL2 DPI changes and implement on Windows #895
  • macOS - macOS: Dpi overhaul #997
  • iOS - iOS: Dpi overhaul #1223
  • Linux X11 - Implement DPI Usability Upgrades for X11 and Wayland #1098
  • Linux Wayland - Implement DPI Usability Upgrades for X11 and Wayland #1098
  • Web - Implement hidpi for web platform #1233
• Added an entry to CHANGELOG.md if knowledge of this change could be valuable to users
• Updated feature matrix, if new features were added or implemented.
• Update DPI module docs to properly describe Winit's new DPI handling system - Use i32 in Position::Physical #1350
• Implement HiDpiFactorChanged on the web

[Osspial]

Mentoring Instructions

For the most part, implementing this should be a matter of following the error messages and converting to physical or logical coordinates as necessary.

Once the main implementation for a platform is complete, this may be a good place to look into fixing #940. However, that isn't strictly necessary if you aren't feeling up to it.