Improve taskresults app

- show created/modified fields in admin
- add verbose output to management command
- add date hierarchy and action filters in admin

gnuviechadmin/taskresults/admin.py

@@ -11,5 +11,10 @@ from .models import TaskResult
 
 @admin.register(TaskResult)
 class TaskResultAdmin(admin.ModelAdmin):
-    list_display = ('task_id', 'creator', 'signature', 'finished', 'state')
-    list_filter = ('finished',)
+    list_display = ("task_id", "creator", "signature", "finished", "state")
+    list_filter = ("finished", "creator")
+    date_hierarchy = "created"
+    readonly_fields = ("created", "modified")
+
+    def has_add_permission(self, request):
+        return False