Fix adjacent views polishing

[AdityaPahilwani]

Is it a bugfix ?

• No

Is it a new feature ?

• Add support for showing adjacent views in horizontal view
• Added 3 new props showAdjacentViews, adjacentViewsWidth, adjacentViewsPadding.

Prop	Default	Type	Description
showAdjacentViews	false	bool	If true it will display adjacent views
adjacentViewsWidth	8	number	Indicates how much width should be displayed of adjacent view, If showAdjacentViews is false it will be ignored.
adjacentViewsPadding	4	number	Indicates the gap between adjacent views, If showAdjacentViews is false it will be ignored.
decelerationRate	'normal'	enum('fast', 'normal'), number	A floating-point number that determines how quickly the scroll view decelerates after the user lifts their finger.

Describe what you've done:

• Width/height of item-Container and lazy-Item-Container will be calculated in the context of showAdjacentViews, adjacentViewsWidth, adjacentViewsPadding.
• Instead of duplicating only 1 element in start and end, now it duplicated 2 elements. So autoplay feature can work with 0 readjusts.
• Duplicate elements, first real element, and last real element will always be visible so when autoplay is on, the user won't see blank spots.
• Unless and until the user swipes hard to scroll to the last duplicate element at start or end, only then they will see a little readjust after scroll but the index position will always be remembered.
• Using snapToOffsets to get the proper swipe feature to display our adjacentViews.

How to test it ?

Have added examples for the same, in the example folder

Snack showcasing the new feature

[Kliorsapir]

Super nice!! :)

[pgandroid1289]

@leecade Please merge this link for adjustcant views