Windows: Use UTF-8 for pipes in CMake, CTest and CPack
Use UTF-8 encoding for pipes. This allows to correctly pass Unicode strings between CMake <=> CTest
even if they can't be represented in current active codepage.
Applications which process CMake pipe output will need to decode it as UTF-8 instead of console's codepage.
This depends on ConsoleBuf::Manager expose ConsoleBuf to be accesible but I'm putting it here for review.