Add spinner or animation to submit form while the user waits.
1. Do we want to use xtermjs for binderlite or something simpler/lighter like an animation that let's the user know more explicitly that they are waiting for a container to be built? A spinning guix gnu logo could be cool.
https://www.w3schools.com/howto/howto_css_loader.asp
https://spin.js.org/https://spin.js.org/