Add images for each supported iOS device for a dark-theme splash screen
Conditionally use light vs dark images based on the `(prefers-color-scheme: dark)`
media query
Note: Once the PWA is installed, it appears that iOS caches the splash screen image for an
unknown period of time, so if you change your device's preferred theme after installation,
the splash screen doesn't update to reflect it. The PWA must be re-installed for
this change to take effect.
SatsAllDay