Fix nav in docs so it doesn't overlap other items (#640)
* Fix nav in docs so it doesn't overlap other items
this is the smallest change I could think of, only allocating space for the hamburger menu when it's visible, otherwise letting the container shrink down to the theme switcher
We missed a couple dependencies
* Found a site demonstrating the same problem we have and how to solve it
* Place docs into a new div with isolation: isolate so that the modal doesn't have a sibling with a z-index
Fix issue where if there was a vertical scrollbar, there was also a horizontal one
* Add some code comments and remove dead code
* don't use vw,vh when we do not need to
* change everything to use new hamburgerButton class instead
* remove unneeded visibility attribute
