Update the file caching app

- Add view to list available caches.
- Add links to view and purge caches.
- Add permissions.
- Add events.
- Add purge task.
- Remove document image clear link and view.
  This is now handled by the file caching app.

Signed-off-by: Roberto Rosario <roberto.rosario@mayan-edms.com>

docs/releases/3.3.rst

@@ -76,6 +76,8 @@ Changes
 - Add platform template to return queues for a worker.
 - Remove task inspection from task manager app.
 - Move pagination navigation inside the toolbar.
+- Remove document image clear link and view.
+  This is now handled by the file caching app.
 
 
 Removals