qt: Renable Windows Foreground Window hacks

* qt/main.cpp, qt/pinentryconfirm.cpp: Use raiseWindow again.
* qt/pinentrydialog.cpp: Renable Foreground Window hacks.

Enabled this again because the focus did
not change to the pinentry window without the attach
thread input stuff. The setup_foreground_window helps though,
so that stays. Either Qt Windows foreign Window Management
is a mess and does not really work or I don't understand it.