Adds a url input source to the FilePond sources list.

The URLInputSource extension can be configured with the URLInputSourceOptions object. 

import { defineFilePond } from 'filepond';
import { locale } from 'filepond/locales/en-gb.js';
import { URLInputSource } from 'filepond/extensions/url-input-source.js';

defineFilePond({
    locale,
    extensions: [
        // Add the URLInputSource extension and configure with URLInputSourceOptions object
        URLInputSource
    ]
})