Countdown app

I added a countdown app/widget for some motivation so you can have something to look forward to! The CSS is definitely lacking so I will work on it once im done with JS.
It was a bit hard to convert every input and change precision but I figured it out thanks to W3S.

I still need to:

• Show a list of the cooldowns in the main window and make them editable and deleteable
• Make the new window closeable & pinnable
• Make the time input optionnal
• Make an icon for the app
• Find a way to save changes? (maybe)