Only display the Remove Question Type menu item on pages where the
question type can be set.

If there is no source set on the tab configuration, the upload
button will no longer be displayed.

So user is redirected to the correct page after uploading data

Refactor the ViewsItems view, which covered the view and edit table, into a separate (non-view) class under tabs/view_and_edit_table.py. When ready, this will plug straight away into the new tabbed page functionality - in the mean time there is a place holder view to display the view where it used to be found.

ViewItem.get_category_options should return the options as we want them - we shouldn't have to process them later. So make sure it returns (short question, short question) as we want both the value and the text to use the short version.

Re-introduce the per-row drop down to update each record's category as well as the mirrored buttons at the bottom of the page. This means that we have a single form that can either do a batch update, or an update of values set per row. The different action is determined by the submit button that was used - which is always named 'action'. Because we have a mirrored select drop down for the batch action, we need to know which one to take into account - so the value of the submit button indiciates which one was clicked, of the form <action>-<placement> (eg. save-top) and the name of mirrored inputs indidicate where they are located, of the form <name>-<placement> (eg. batchaction-bottom). The ViewItems class has a static method to find the active placement and rename the parameters accordingly. Some of the old code was re-introduced, though some of it was refactored (eg. what used to be get_categories, to fetch each row's selected category, has been moved to ItemTable to parallel get_selected, and is now named get_row_select_value (it's a more generic version, looking at the future when we'll update the region with the same mechanism.)

Rename select_action to select_item which makes more sense. Rename the checkbox itself select_item_id to allow other types of selectes in the future. Move the code to determing selected items into ItemTable since this is where the form is generated, and we know how it was build.

Previously were strings - django tables2 requires datetime objects

ItemTransport clas --> transport.items module

Replace with ItemTransport object, which needs to be instantiated. I
think it can be reused between calls to its methods so there's no need
to create new ones all over the place, but that's what I have done so
far. I'm a bit uncertain about module level variables, and not
everything is contained in a class.