libudev-list: move libudev-list related definitions to libudev-list-internal.h

This also rename libudev-private.h to libudev-util.h, and cleanups
several unnecessary headers from udev.h and libudev-util.h

src/libudev/libudev-queue.c

@@ -9,10 +9,11 @@
 #include <sys/inotify.h>
 #include <unistd.h>
 
+#include "libudev.h"
+
 #include "alloc-util.h"
 #include "fd-util.h"
 #include "io-util.h"
-#include "libudev-private.h"
 
 /**
  * SECTION:libudev-queue