DevTools+LibGUI: Make ProcessChooser a general Dialog in LibGUI

Moves ProcessChooser and RunningProcessesModel to LibGUI and
generalizes their construction for use by other apps. Updates
Profiler to reflect the change and use its new icons.

Libraries/LibGUI/CMakeLists.txt

@@ -51,9 +51,11 @@ set(SOURCES
     MultiView.cpp
     Notification.cpp
     Painter.cpp
+    ProcessChooser.cpp
     ProgressBar.cpp
     RadioButton.cpp
     ResizeCorner.cpp
+    RunningProcessesModel.cpp
     ScrollableWidget.cpp
     ScrollBar.cpp
     Shortcut.cpp