Adding cosmoDC2 tutorial to the page

Author: bsipocz

index.md

@@ -25,17 +25,20 @@ tutorials/irsa-sia-examples/siav2_seip
 
 ```
 
-<!---
 ### Catalogs
 
 ```{toctree}
 ---
 maxdepth: 1
 ---
 
+tutorials/cosmodc2/cosmoDC2_TAP_access.md
 
 ```
 
+
+<!---
+
 ## Visualizations
 ```{toctree}
 ---