Implement IuCS (large refactoring and addition)

osmo-nitb becomes osmo-msc
add DIUCS debug log constant
add iucs.[hc]
add msc vty, remove nitb vty
add libiudummy, to avoid linking Iu deps in tests
Use new msc_tx_dtap() instead of gsm0808_submit_dtap()
libmgcp: add mgcpgw client API
bridge calls via mgcpgw

Enable MSC specific CTRL commands, bsc_base_ctrl_cmds_install() still needs to
be split up.

Change-Id: I5b5b6a9678b458affa86800afb1ec726e66eed88
diff --git a/src/libcommon/debug.c b/src/libcommon/debug.c
index dc79a84..7dbbc6a 100644
--- a/src/libcommon/debug.c
+++ b/src/libcommon/debug.c
@@ -184,6 +184,11 @@
 		.description = "Visitor Location Register",
 		.enabled = 1, .loglevel = LOGL_DEBUG,
 	},
+	[DIUCS] = {
+		.name = "DIUCS",
+		.description = "Iu-CS Protocol",
+		.enabled = 1, .loglevel = LOGL_DEBUG,
+	},
 };
 
 static int filter_fn(const struct log_context *ctx, struct log_target *tar)
diff --git a/src/libcommon/gsm_data.c b/src/libcommon/gsm_data.c
index f6fde37..b5bf059 100644
--- a/src/libcommon/gsm_data.c
+++ b/src/libcommon/gsm_data.c
@@ -449,3 +449,10 @@
 		rev_lev = (cm->classmark2[0] >> 5) & 0x3;
 	return rev_lev >= 2;
 }
+
+const struct value_string ran_type_names[] = {
+	OSMO_VALUE_STRING(RAN_UNKNOWN),
+	OSMO_VALUE_STRING(RAN_GERAN_A),
+	OSMO_VALUE_STRING(RAN_UTRAN_IU),
+	{ 0, NULL }
+};