Add quick section links, top arrow and footer to the API swagger page

[TheRolfFR]

I use fairly often the API page to watch the data type and values. However the number of sections has grown a lot since v2 start.

We could need:

• [ ] Some kind of menu or links to navigate would be appreciated
• [ ] A top arrow to go to the top of the page
• [ ] A descriptive footer like the documentation one