Styling & formatting for GBE

[leohhhn]

Description

Here are some minor styling & formatting improvements that could be implemented for GBE.

1. Home page organization: I'm not a designer by any means, but I think it would be awesome to have a large banner, and below it have the sections listed horizontally. The sections can be dropdowns, or cards with a short section description that people can open up. I can ask the design team for some ideas/figma files.
2. Weird gap between file name & line 1 in code

3. Code options could be automatically expanded in the code viewer, since there is a lot of unused space

4. Possibly add a "Open in Playground" button
5. While inside a specific tutorial, have a sidebar with the other tutorials in the section, for easier navigation
6. Interlinking with the Official docs & Playground

@zivkovicmilos, since you're busy, I will see with @alexiscolin if he has a bit of bandwidth to work on the frontend side of things.

[alexiscolin]

Other Playground issues may be fixed with the new embedded playground that will come soon.
https://github.com/gnostudio/studio/pull/970
I would wait for this PR to be merged before improving it.