Add offline keys definitions

display offline file keys definitions and units from aanet version 2 documentation

README.rst

@@ -110,9 +110,12 @@ Overview of offline files
 Offline files contain data about events, hits and tracks. 
 
 .. csv-table:: events keys definitions and units
-   :file: https://git.km3net.de/km3py/km3io/blob/add-offline-keys-definitions/km3io/definitions/events.csv
-   :widths: 20, 20, 60
-   :header-rows: 1
+   :header: "type", "name", "definition"
+   :widths: 20, 20, 40
+
+    "int", "id", "offline event identifier"
+    "int", "det_id", "detector identifier from DAQ"
+
 
 DAQ files reader
 ----------------