Dashboard management minor issues

Overview:

Following the implementation of managed dashboards, there are a number of small UX issues that should be addressed:

1. On the Create/Edit dashboard page, the Dashboard name field should not allow the user to enter more than 25 characters (currently it allows the user to enter more but displays a warning - to be consistent with other apps it should simply prevent more than 25 chars being entered)
2. The Edit dashboard view should be headed with "Edit dashboard - <dashboard name>" rather than "Create dashboard" as currently
3. The Manage dashboards view should be headed "Manage dashboards" rather than "Order widgets" as currently
4. On deleting a dashboard the modal dialogue should be headed "Delete dashboard - <dashboard name>" rather than just "Delete dashboard" as currently
5. In the Actions menu, the headings should be formatted using the same style as the heading "Show columns" in the screen shot below (taken from the Orders app)
   
6. Correct a typo in the infopop text for the "Short name" field: "The short name will be used to create the menu button for the dashboard. The number of characters is limited to 25 maximum"