[Feature Request] Add Custom Splash Screen

[landenai]

In order to better understand cold app start time and how it interacts with splash screens, a custom splash screen activity should be added to app launch process

• This screen should be shown before the main application landing page
• This screen should be a custom activity and should not use the SplashScreen API
• This screen should show for some meaningful amount of time (1 second) before being closed in favor of the main application landing page