D8281: Allow to use IcoTool for Windows icons

[Aleix Pol Gonzalez]

apol added a reviewer: Windows.

REPOSITORY
  R240 Extra CMake Modules

REVISION DETAIL
  https://phabricator.kde.org/D8281

To: vpinon, dfaure, apol, kfunk, #windows
Cc: #frameworks, #build_system