Remove PkgConfig dependence on Windows

See merge request !411

The module is used only under Windows.

Also, renamed `findPkgVersion` -> `find_pkg_version` for conformity with
CMake function names.

Integrate layer oriented sample editor into SampleView

See merge request !414

introduce layer oriented sample editor

See merge request !413

introduce WidgetMoverButton (to realize the "move layer" feature in the upcoming layer oriented sample editor)

More preparations for layer oriented sample editor

See merge request !412

Overhaul UI: simplify displaying the results of jobs

See merge request !410

This module is a simple replacement for `PkgConfig`.

`PkgConfig` works properly only on Linux. On Windows, there is no guarantee that
it works properly. It is also not necessary.

Related to issue #133

Add the possibility to show the empty widget in ItemComboWidget also for other items (e.g. running jobs)

Add a blank widget to ItemComboWidget for the case that a nullptr SessionItem is set as the current item (instead of the show/hide logic)

Merge remaining funcionality of JobOutputDataWidget into JobResultsPresenter and delete obsolete JobOutputDataWidget

Remove ItemStackPresenter (which was only used in "single widget mode" anyway) from JobOutputDataWidget

Descriptors3

See merge request !409