Restructuring of platform definitions

The CourierPlatformDefs folders have been removed from the applications. The content is platform dependent and not application dependent. With this, every application can share the platform definitions. With this change we also removed the force of CMake flags in the platform definitions. These flags are not platform but application specific. This might have impact on your applications as the default settings may have changed. The CourierPlatformDefs name might have also changed to a more generalized name for the device (e.g. removal of some OS information in the platform name).

Toolchain files are moved from cgi_studio_candera to the appropriate device in cgi_studio_device.