Add example plugin with documentation

scripts/plugins/example/plugin.lua

@@ -0,0 +1,32 @@
+--
+-- (C) 2019 - ntop.org
+--
+
+-- This file contains the plugin metadata information.
+
+-- NOTE: Plugins are loaded at startup, any change to this plugin
+-- can be applied by restarting ntopng or by manually reloading the
+-- plugins from http://127.0.0.1:3000/lua/plugins_overview.lua .
+
+return {
+  -- The (unique) name of the plugin
+  title = "Example Plugin",
+
+  -- A description of the functionalities offered by the plugin
+  description = "An example to show how to write ntopng plugins",
+
+  -- The author of the plugin. For emails use the format: 'Name Surname <me@domain.com>'
+  author = "ntop",
+
+  -- An incremental number indicating the plugin version.
+  version = 1,
+
+  -- A list of plugin keys which this plugin depends on. A plugin key
+  -- corresponds to the directory name of the plugin (e.g. the key of
+  -- this plugin is "example")
+  dependencies = {"builtin_types"},
+
+  -- A disabled plugin will not be loaded.
+  -- Comment this and reload the plugins to activate this test plugin.
+  disabled = true,
+}