Enhancement: Remove default props from functional components

[marteinn]

According to facebook/react#16210 defaultProps on functional components are deprecated and will be removed in a feature version of React. defaultProps should instead replaced with default values on arguments.

Quick example:

Functional component with defaultProps should go from this:

const Accordion = ({title, text, open, id}) => {
    ...
    
Accordion.defaultProps = {
    title: '',
    text: '',
    open: false,
    id: 'accordion',
};

to this:

const Accordion = ({title = '', text = '', open = false, id = 'accordion'}) => {
    ...