Add clusterio module with API for lua code

Add a shared API for lua code through a module named clusterio.

modules/clusterio/api.lua

@@ -0,0 +1,17 @@
+local api = {}
+
+
+-- Table of events raised by clusterio
+api.events = {
+    -- Raised after the name and id of an instance has been updated
+    -- This may occur even if the id and name didn't change.
+
+    -- Event data:
+    --   instance_id: The id of the instance.
+    --   instance_name: the name of the instance.
+    on_instance_updated = script.generate_event_name(),
+}
+
+
+return api
+