Update JS code file structure + Creating the Notes app functionality

I spent some time updating the structure of my js file by reordering some code and also creating functions for any repeated tasks such as initialising windows. I also worked on my Notes app and played around with some border and outline properties to see what combination of styles would make it easier for users to edit in the app. I ended up with going for a left border indicator type of thing (the colours in the screenshot below aren’t final since I haven’t worked on the overall style of my OS yet so I just went with grey and black)