Appearance: Fix form CSS media rendering

Fix the way the form CSS contained in the media attribute
is rendered. This is now an interator and not a single value.
Replace the current method with a for loop.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/document_states/literals.py

@@ -9,3 +9,4 @@ WORKFLOW_ACTION_WHEN_CHOICES = (
     (WORKFLOW_ACTION_ON_ENTRY, _('On entry')),
     (WORKFLOW_ACTION_ON_EXIT, _('On exit')),
 )
+WORKFLOW_IMAGE_TASK_TIMEOUT = 60