Add more assets to the app?

[GAA251]

Description

Currently, youtube-webos only provides a icon and a largeIcon, which means when you use the app, most of the textures listed below are just webOS defaults:

Some of these assets being provided by the project might be a nice-to-have QoL feature.

splashBackground (The splash screen when the app is being launched, default is a static spinner icon, the official YouTube app just uses a gray background that matches the app's theme) playIcon (Used in search results I assume? - YouTube's official app uses a favicon) imageForRecents (Used in the recent apps list) bgImage mediumLargeIcon (I assume this is for HiDPI/HiRes displays) extraLargeIcon (I assume this is for HiDPI/HiRes displays)

These are the textures that are used in the YouTube official webOS app that do not have youtube-webos equivalents.