Introduce LTE Transmission Mode and RLC DRB mode params

Change-Id: I38f247f266ba736cdbb6f36ba5673b8fd46a8d67
diff --git a/example/scenarios/mod-enb-txmode@.conf b/example/scenarios/mod-enb-txmode@.conf
new file mode 100644
index 0000000..e0c8d01
--- /dev/null
+++ b/example/scenarios/mod-enb-txmode@.conf
@@ -0,0 +1,3 @@
+modifiers:
+  enb:
+  - transmission_mode: ${param1}