[CMake] dune_library_add_sources: Add some sanity checks

This patch adds some sanity checks to dune_library_add_sources:

- Make sure that dune_enable_all_packages has been called

- Test whether the library has been declared in the MODULE_LIBRARIES
  argument of dune_enable_all_packages

In case of an error, the macro aborts the CMake run with a fatal error.