function getChildFileFromName(files, fileName) {
	const index = files.findIndex(file => file.name === fileName);
	return { index, file: files[index] };
}
Returns the file object and it's index that is direct child of passed files array with name as passed fileName.
If not found, returns -1
@param {array} files files structure for an item
@param {string} fileName File/folder name