Use forwardRef to underlying RN components

## 🚀 Feature Proposal
Basically the same request as: https://github.com/akveo/react-native-ui-kitten/issues/955
> My suggestion is to use forwardRef for these components to make them cleaner and more compatible (any API changes in RN won't need changes in those components).

## Motivation

In my case I'm running into trouble with a component that expects a RN Input. I'd like to give it a UI Kitten one instead but need a forwardRef for things to work. Generally as noted previously the components will play nicer if they forward ref to the underlying component generally.

## Example

```jsx
import React from 'react';
import { Input } from '@ui-kitten/components';
import ReactPhoneInput from 'react-phone-number-input/react-native-input'

export const PhoneInput = observer((props) => )

```