Cannot add refs to a Textarea

[garthtee]

A ref cannot be added to a Textarea as it's a functional component. Using form libraries to control an input/textarea requires form inputs to allow refs to be passed. I've had a look at the Input component and it has a forward ref.

I'm happy to implement a forwardRef for this if everyone accepts this as an issue!

[nlopin]

Will be handled as a part of #169