Port existing autotests to new xdg-shell helpers
Non-core protocol wrappers in KWayland::Client are obsolete. C++ client-side code for protocols such as xdg-decoration, xdg-shell, and so on must be generated in-place where it's needed.
For the most part, this merge request is just boring s/createXdgShellStable/createXdgToplevelSurface/g. I intend to squash the commits before merging this MR.
Edited by Vlad Zahorodnii