This allows messages to be stashed in the session and displayed on a
following request. This will be pivotal in implementing the PRG
(post-redirect-get).

* Make the "Items" tab the default
* Drop the "Showing ..." text and add a count to the items tab
* Redirect to "Items" tab when creating a new list
* Add a new list item by ajax rather than refresh

Also fixup some layout issues in filter management

View new task in the context of ticket view.

Remove manual roll-up on tickets page since it's auto-added.

Add danger to delete actions.

Revert this commit once fixed.

Support edit/update of dynamic data

* Preserve external storage flag on field configuration
* User gridlayout to render task's forms
* Use new roles for task's nav

Credit: Jared Hancock <jared@osticket.com>