Add day component props for memo equality control

[brianangulo]

Hi, @Inbal-Tish @ethanshar I would like to hear your thoughts on this. Thank you for all your work contributing to open source.

The Problems:

• The Day component will often cause performance issues coming from it not properly memoizing leading to unnecessary rerenders.
• Passing additional data to a custom day component would require declaring it as a function on the parent component and passing it to the Calendar. This is inconvenient and inefficient.

Solutions:

• Adding a prop dayComponentMemoEqualityFn that allows the user to override the default equality function thus giving the consumers more fine control over memoization of the component
• Adding a prop extraData inspired by react-native Flatlist's extraData to give the consumers a better and guided way of passing data

[brianangulo]

Could you take a peek please @M-i-k-e-l 🙏 ?