common: Move debug and userpref code into libinternalcommon

src/service.c

diff --git a/src/service.c b/src/service.c
index abd1696..5bc7aea 100644
--- a/src/service.c
+++ b/src/service.c
@@ -26,7 +26,7 @@
 
 #include "service.h"
 #include "idevice.h"
-#include "debug.h"
+#include "common/debug.h"
 
 /**
  * Convert an idevice_error_t value to an service_error_t value.