Revert "main navigation: liens communs à tout luminy.org"

This reverts commit 07acfa01.

_data/navigation.yml

 # mashead links
 main:
+  - title: "Le CCL"
+    url: /ccl/
+  - title: "Activités"
+    url: /ccl/activites/
   - title: "Agenda"
     url: /agenda/
-  - title: "Le Grenier"
-    url: /grenier/
-  - title: "À Propos"
-    url: /about/
-
-
+  - title: "Contacts"
+    url: /ccl/l-asso/contacts/
 
 navs:
   - name: "ccl"