CMake: Allow to run staging installation in CMakeInstallStep

User configurable, on by default (only) for cases where build and run
device are different.

The staging dir is by default a randomly named directory on the build
device, but can be changed by the user if needed.

Overall, this does not change anything for a pure local setup (but
would let the user opt-in into staging, too)

Change-Id: Ic1c5fd1f1261e067692710c9e3aa9d821897478d
Reviewed-by: Cristian Adam <cristian.adam@qt.io>

src/plugins/cmakeprojectmanager/cmakeinstallstep.cpp

@@ -93,6 +93,7 @@ void CMakeInstallStep::finish(ProcessResult result)
     emit progress(100, {});
     AbstractProcessStep::finish(result);
 }
+
 QWidget *CMakeInstallStep::createConfigWidget()
 {
     auto updateDetails = [this] {