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>

mayan/apps/file_caching/links.py

@@ -0,0 +1,22 @@
+from __future__ import unicode_literals
+
+from django.utils.translation import ugettext_lazy as _
+
+from mayan.apps.navigation.classes import Link
+
+from .icons import icon_cache_purge, icon_file_caching
+from .permissions import permission_cache_purge, permission_cache_view
+
+link_caches_list = Link(
+    icon_class=icon_file_caching, permissions=(permission_cache_view,),
+    text=_('File caches'), view='file_caching:cache_list'
+)
+link_cache_purge = Link(
+    icon_class=icon_cache_purge, kwargs={'cache_id': 'resolved_object.id'},
+    permissions=(permission_cache_purge,), text=_('Purge cache'),
+    view='file_caching:cache_purge'
+)
+link_cache_multiple_purge = Link(
+    icon_class=icon_cache_purge, text=_('Purge cache'),
+    view='file_caching:cache_multiple_purge'
+)