React-native-snap-carousel: Add standard flat layout

[xerus2000]

This is a Feature Request.

When using the carousel, I noticed that there is no simple flat animation, so that, when scrolling, the items only move horizontally without being scaled or other fancy stuff.
I know that I can probably create this by myself, but it sounds like a trivial yet pretty common use-case, that should imo be supported out of the box.

[richeterre]

You can simply set inactiveSlideScale={1} to make items move horizontally.

[xerus2000]

Thanks!