Initial Open5GS support

Change-Id: Iff8b88dc22d8f156572839abb48b0c1377c55e33
diff --git a/sysmocom/scenarios/cfg-epc-db@.conf b/sysmocom/scenarios/cfg-epc-db@.conf
new file mode 100644
index 0000000..e6c79c4
--- /dev/null
+++ b/sysmocom/scenarios/cfg-epc-db@.conf
@@ -0,0 +1,3 @@
+config:
+  epc:
+    db_host: ${param1}