feature: Add a splash screen

[BlakeBarrett]

Ask

As a Lore user, I want to be greeted with an impressive splash screen, so that I know I'm about to drop some Lore.

Notes:

• Background should be: Theme.of(context).primaryColor
• Attached splash screen image should be over it (yes it will be orange on orange).
• Use this library https://pub.dev/packages/flutter_native_splash