Docker compose bbsim system test includes radius

Useful for testing AAA/EAPoL with BBSIM

Change-Id: I81030b0615d8e544877f1084d49b105c6689e79e
diff --git a/compose/radius-clients.conf b/compose/radius-clients.conf
new file mode 100644
index 0000000..345c2ea
--- /dev/null
+++ b/compose/radius-clients.conf
@@ -0,0 +1,3 @@
+client 0.0.0.0/0 {
+  secret = SECRET
+}