move headers to include/osmocom/hlr

Apply the same headers structure that we keep in most Osmocom source trees:
Keep noinst_HEADERS in include/osmocom/hlr and include them using
  #include <osmocom/hlr/*.h>

The only header kept in src/ is db_bootstrap.h, because it is generated during
build time. If it was built in include/osmocom/hlr, we would need db.o to
depend on db_bootstrap.h in a different subdir, which automake can't do well.

Change-Id: Ic912fe27f545b85443c5fb713d8c3c8aac23c9ad
diff --git a/src/db_auc.c b/src/db_auc.c
index 2cf7143..e3a840e 100644
--- a/src/db_auc.c
+++ b/src/db_auc.c
@@ -26,10 +26,10 @@
 
 #include <sqlite3.h>
 
-#include "logging.h"
-#include "db.h"
-#include "auc.h"
-#include "rand.h"
+#include <osmocom/hlr/logging.h>
+#include <osmocom/hlr/db.h>
+#include <osmocom/hlr/auc.h>
+#include <osmocom/hlr/rand.h>
 
 #define LOGAUC(imsi, level, fmt, args ...)	LOGP(DAUC, level, "IMSI='%s': " fmt, imsi, ## args)