Add API abstraction for platforms "recent files" list

The big three platforms all have some version of this:

• Linux/FreeDesktop spec:
  • https://freedesktop.org/wiki/Specifications/desktop-bookmark-spec/
  • $XDG_USER_DATA/recently-used.xbel
• Windows
  • "Quick Access" section of Explorer and file selection dialogs
• macOS
  • "Recents" section of Finder and file selection dialogs

Often times the platform automatically manages this well, but there are cases where it doesn't update automatically (like when a file is opened by dragging and dropping) and times when it would be nice to query that list