implement subscriber vty interface, tests

Implement VTY commands for subscriber manipulation:
- create / delete subscriber
- modify MSISDN
- add/edit/remove 2G and 3G authentication data
- show by IMSI, MSISDN or DB ID.
(enable/disable CS/PS and purge/unpurge to follow later.)

Implement VTY unit tests for the new commands using new
osmo_verify_transcript_vty.py from osmo-python-tests.

Depends: libosmocore I1e94f5b0717b947d2a7a7d36bacdf04a75cb3522
         osmo-python-tests Id47331009910e651372b9c9c76e12f2e8964cc2c
Change-Id: I42b3b70a0439a8f2e4964d7cc31e593c1f0d7537
diff --git a/src/hlr_vty.c b/src/hlr_vty.c
index 946117e..a5eb26f 100644
--- a/src/hlr_vty.c
+++ b/src/hlr_vty.c
@@ -26,6 +26,7 @@
 #include <osmocom/vty/logging.h>
 
 #include "hlr_vty.h"
+#include "hlr_vty_subscr.h"
 
 static struct hlr *g_hlr = NULL;
 
@@ -135,4 +136,6 @@
 	install_default(GSUP_NODE);
 
 	install_element(GSUP_NODE, &cfg_hlr_gsup_bind_ip_cmd);
+
+	hlr_vty_subscriber_init(hlr);
 }