Functional component for a modern approach

[finnholland]

Creating a more modern react native module to utilise useState and const statements.

• Added a functional component version of the index.ts to better service modern react native compared to class based.
• Also split out the types into a types.ts so they can be shared across the two files (this is optional but nicer to manage imo)

Wasn't sure on naming conventions so feel free to veto those.
I have tested using my example but will confirm with the example in the package later today.