Migrate conan with new CMakeDeps generator
End user should now use either the cmake_find_package or the cmake_deps conan generator to build their project.
- All targets are lowercase to be conform with the conan style
- GTest has been updated to 1.11
- This change makes it possible working with pylene as a conan editable package
Breaking changes
- Comsumer should now link with pylene::core, pylene::io-freeimage ...