Add a simple graph testing plugin, and use critical instead of alarm

tools/munin-node-from-hell/basic.conf

@@ -0,0 +1,15 @@
+# 
+# Initialise plugins that test the basic functions of Munin.
+#
+# 
+
+[instance:basic]
+pluginprofile = basic
+port = 4000
+
+[pluginprofile:basic]
+plugins = always_warning, always_critical, graph_area
+
+[base]
+# when building an example config with --muninconf, what hostname to output.
+hostname = localhost