score: Create object implementation header

Move implementation specific parts of object.h and object.inl into new
header file objectimpl.h.  The object.h contains now only the
application visible API.

testsuites/sptests/sp41/init.c

@@ -11,9 +11,10 @@
 #include "config.h"
 #endif
 
-#define __RTEMS_VIOLATE_KERNEL_VISIBILITY__
 #include <tmacros.h>
 
+#include <rtems/score/objectimpl.h>
+
 /* forward declarations to avoid warnings */
 rtems_task Init(rtems_task_argument argument);
 void iterator(Thread_Control *thread);