Add motd, prompt and haveged

Change-Id: I82b2a6c5beaa0faeece8834d289c9b5d4be86274
diff --git a/linux/system/haveged.yml b/linux/system/haveged.yml
new file mode 100644
index 0000000..5c0be15
--- /dev/null
+++ b/linux/system/haveged.yml
@@ -0,0 +1,5 @@
+parameters:
+  linux:
+    system:
+      haveged:
+        enabled: true