Draft: Replace custom hamburger/control menu with KHamburgerMenu
This merge request is mostly to allow easy testing of frameworks/kconfigwidgets!25. The code is not meant to be final.
Here the new KHamburgerMenu from KConfigWidgets replaces the custom Dolphin control menu.
I also took the freedom to reduce the contents of the hamburger menu firstly to highlight how the new menu at the bottom helps us to keep the menu a reasonable length without making the discovery of all those actions impossible.
While I do think the changes to the contents are an improvement it probably doesn't make a lot of sense to discuss this until frameworks/kconfigwidgets!25 is merged.
(same video as in frameworks/kconfigwidgets!25)