Give our loose headers proper library homes - #9309

The loose headers now have more distinct uses and with that its more sane to move them where they fit. Config.h is now only used for XWindows parts of the platform lib. VersionInfo would now make more sense as part of common lib.

• Use a list of dirs when calling include_directories in src/CMakeLists.txt
• Mv src/lib/VersionInfo.h.in -> src/lib/common/VersionInfo.h.in
  • Adjust VersionInfo.h.in to respect the clang format rules.
• Mv src/lib/Config.h.in -> src/lib/platform/XWindowsConfig.h.in
  • Use #define to create the defines
  • Add #pragma once
  • Included only with X11_Platform support
  • Remove its unneeded inclusion in gui/MainWindow.cpp
  • Remove unused define HAVE_CONFIG_H