Profiler: Turn the "choose a process" functionality into a GUI::Dialog

This feels a bit nicer and make it possible to reuse this in other
places as well. :^)

DevTools/Profiler/CMakeLists.txt

@@ -1,6 +1,7 @@
 set(SOURCES
     DisassemblyModel.cpp
     main.cpp
+    ProcessChooser.cpp
     Profile.cpp
     ProfileModel.cpp
     ProfileTimelineWidget.cpp