implement support for 3-digit MNC with leading zeros

Add 3-digit flags and use the new RAI and LAI API from libosmocore throughout
the code base to be able to handle an MNC < 100 that has three digits (leading
zeros).

Note that in gbproxy_test.ok, 0-0 changes to 000-000 instead of 000-00, because
the parsed ra buffer is 000000 which results in 000-000, while 00f000 would
result in 000-00. IOW this is expected.

Change-Id: I7437dfaa586689e2bef0d4be6537e5577a8f6c26
diff --git a/tests/gbproxy/gbproxy_test.ok b/tests/gbproxy/gbproxy_test.ok
index ff86b67..5d77dc9 100644
--- a/tests/gbproxy/gbproxy_test.ok
+++ b/tests/gbproxy/gbproxy_test.ok
@@ -7249,7 +7249,7 @@
   Add TLLI 1, IMSI 1
   Add TLLI 2, IMSI 1 (should replace TLLI 1)
   Peers:
-    NSEI 0, BVCI 20, not blocked, RAI 0-0-0-0
+    NSEI 0, BVCI 20, not blocked, RAI 000-000-0-0
       TLLI cache size                 : 1
       TLLI-Cache: 1
         TLLI c000162e, IMSI 03242526, AGE 0, IMSI matches
@@ -7258,7 +7258,7 @@
   Add TLLI 1, IMSI 1
   Add TLLI 1, IMSI 2 (should replace IMSI 1)
   Peers:
-    NSEI 0, BVCI 20, not blocked, RAI 0-0-0-0
+    NSEI 0, BVCI 20, not blocked, RAI 000-000-0-0
       TLLI cache size                 : 1
       TLLI-Cache: 1
         TLLI c00004d2, IMSI 06272829, AGE 0, IMSI matches
@@ -7267,7 +7267,7 @@
   Add TLLI 1, IMSI 1
   Add TLLI 2, IMSI 2 (should replace IMSI 1)
   Peers:
-    NSEI 0, BVCI 20, not blocked, RAI 0-0-0-0
+    NSEI 0, BVCI 20, not blocked, RAI 000-000-0-0
       TLLI cache size                 : 1
       TLLI-Cache: 1
         TLLI c000162e, IMSI 06272829, AGE 0, IMSI matches
@@ -7276,7 +7276,7 @@
   Add TLLI 1, IMSI 1 (should expire after timeout)
   Add TLLI 2, IMSI 2 (should not expire after timeout)
   Peers:
-    NSEI 0, BVCI 20, not blocked, RAI 0-0-0-0
+    NSEI 0, BVCI 20, not blocked, RAI 000-000-0-0
       TLLI cache size                 : 1
       TLLI-Cache: 1
         TLLI c000162e, IMSI 06272829, AGE 1, IMSI matches
@@ -7286,7 +7286,7 @@
   Add TLLI 2, IMSI 2 (should expire after timeout)
   Add TLLI 3, IMSI 3 (should not expire after timeout)
   Peers:
-    NSEI 0, BVCI 20, not blocked, RAI 0-0-0-0
+    NSEI 0, BVCI 20, not blocked, RAI 000-000-0-0
       TLLI cache size                 : 3
       TLLI-Cache: 3
         TLLI c0000d80, IMSI 12345678, AGE 0, IMSI matches
@@ -7294,7 +7294,7 @@
         TLLI c00004d2, IMSI 03242526, AGE 2, IMSI matches
   Remove stale TLLIs
   Peers:
-    NSEI 0, BVCI 20, not blocked, RAI 0-0-0-0
+    NSEI 0, BVCI 20, not blocked, RAI 000-000-0-0
       TLLI cache size                 : 1
       TLLI-Cache: 1
         TLLI c0000d80, IMSI 12345678, AGE 0, IMSI matches