✨ (expo,web): Double spread support and unify reader interfaces

[aaronleopold]

Web:

• Refactor image reader header, footer, and other controls-related UI elements to better match mobile app patterns
• Extend double spread layout support to align with mobile app (auto, always, and off)
  • Move to the pageSets pattern I used for expo
• Add support for elapsed reading timer
• Add full screen toggle ([FEATURE] Full screen toggle for Android tablets #566)

Expo:

• Add constants for tailwind colors)
• Add misc development user settings (reduced animations, image cache options, etc)
• Switch to FasterImageView where feasible
  • Long term I don't want to rely on two libraries, however I'm waiting on the following before I can remove expo-image:
    • [FEATAURE] Support headers in prefetch candlefinance/faster-image#73
    • [FEATAURE] Support contentPosition for image alignment in viewbox candlefinance/faster-image#75
• Add support for double spread layout
• Pull in @shopify/flash-list for some lists where feasible
• Swap majority of async storage to react-native-mmkv
• Add lottie splash

Misc:

• Refresh website landing page