This simplifies focus related logic a bit. Instead of differentiating
between wayland and internal window focus, simply maintain window focus
that works both with regular wayland windows as well as the ones created
by kwin.
Add `tabletToolEvent()` to DecorationEventFilter class so it can handle
tablet events.
Add `tabletToolEvent()` to MoveResizeFilter class to avoid incorrect
titlebar highlight after a window is resized by using a stylus.
Add `tabletToolEvent()` to WindowActionInputFilter class so window focus
can be changed by clicking on the window content area when using a stylus.
Add `update()` to `TabletInputRedirection::tabletToolEvent()` to enable
switching window focus by using a stylus.
BUG: 432104
Once in a while, we receive complaints from other fellow KDE developers
about the file organization of kwin. This change addresses some of those
complaints by moving all of source code in a separate directory, src/,
thus making the project structure more traditional. Things such as tests
are kept in their own toplevel directories.
This change may wreak havoc on merge requests that add new files to kwin,
but if a patch modifies an already existing file, git should be smart
enough to figure out that the file has been relocated.
We may potentially split the src/ directory further to make navigating
the source code easier, but hopefully this is good enough already.
