When rules configuration is invoked from window `Alt+F3` menu,
we call a custom binary `kwin_rules_dialog` which currently provides
only the rule edition dialog by embedding `RulesEditor.qml` within a
QQuickView.

This MR changes that behavior to call the full KCM from the menu.
The code to match previous rules, or compose a new one based on window
properties has been ported to the KCM from the dialog, so the overall
interaction is similar.

It has several advantages:
 - uses only one entry-point to the code
 - adds discoverability to the full KCM (I guess many users know how to
   create a rule, but not where to delete it later)

And a drawback:
 - only one instance of the KCM can be called at a time, so it will show an
   error when calling it from two different windows, or if the KCM is open
   in System Settings

This drawback can be solved after adding argument passing via dBus in KCM
infraestructure.

BUG: 433837
CCBUG: 417923