I would like you to create a sample plugin called 'featured-posts' that includes all the necessary functionality. The goal is to develop a simple WordPress plugin that allows site administrators to select and display a list of featured posts on their website. The plugin should be easy to install and configure, and allow administrators to select featured posts through the WordPress admin panel.

function featured_posts_widget() {
	register_sidebar_widget(
		'featured_posts_widget',       
		'Featured Posts',        
		'display_featured_posts_widget'  
		);
}