add snapshot data passed to template from /danger/manage-snapshots.

This data is just a list of the directory names for each snapshot stored in the
/snapshots directory -- only deals with HTTP GET here.

src/web.lisp

@@ -1667,12 +1667,14 @@
 	     (append (auth:auth-user-data)
 		     `(:alert ,alert
 		       :system-data ,(nera:system-data)
-		       ;; Snapshot data goes here...
-                       ))))
-  ;; Not Authorised
-  (progn
-    (utils:set-alert "You are not authorised to view this page." "error")
-    (redirect "/login"))))
+                       :snapshots
+                       ,(reverse
+                         (storage::get-directory-names
+                          (storage::get-raw-directories "snapshots/")))))))
+   ;; Not Authorised
+   (progn
+     (utils:set-alert "You are not authorised to view this page." "error")
+     (redirect "/login"))))
 
 (defroute ("/danger/take-snapshot" :method :POST) ()
   (destructuring-bind