[wayland] Implement maximize rules
Summary:
There is still one small issue that has to be addressed in the future:
xdg-toplevel doesn't have states like MAXIMIZED_VERT or MAXIMIZED_HORZ,
thus Window Rules KCM should display only single maximize rule(not two)
for wayland clients.
Test Plan: The new tests pass.
Reviewers: KWin, davidedmundson
Reviewed By: KWin, davidedmundson
Subscribers: kwin
Tags: KWin
Differential Revision: https://phabricator.kde.org/D19414