Add re-ordering support to our existing 'Members' admin view

[dannylamb]

If you go to the 'Members' tab for an object, you get an admin view with all of the members belonging to an object. According to this issue for the weight module, you can configure the view to become a drag 'n drop interface for re-ordering children. Add this to our view so we can re-order pages.

[dannylamb]

Depends on #1261

[dannylamb]

Linking to #932

[seth-shaw-unlv]

We have a complication. Our new weight_field uses the 'integer' field type instead of the weight module's 'weight' field type. This is good in that we can force it to conform to the semantic requirements of http:purl.org/co/index but this blocks us from using the weight module's drag-n-drop functionality.

Two possible resolutions:

1. Change the field_weight to use the weight field type. Pros: we get to use drag-n-drop. Con: it doesn't fit the semantics of http://purl.org/co/index; however, we can alleviate this by using https://schema.org/position instead which would take any integer value.
2. Port the weight module's drag-n-drop to use integers with our configured min/max settings. Pro: we get to use drag-n-drop and keep our integer-based field. Con: more code we have to support ourselves.

Between the two, I would prefer the former over the latter.

[dannylamb]

I'd make it a weight field. I always opt for the least code solution.

[seth-shaw-unlv]

We have three UI options for creating a re-order page:

• We can add it to the existing Members Tab so that you would have a top area for bulk actions and a bottom area for re-ordering (we can create a label for it, it just isn't shown here):

- We can just create a link on the members tab to the re-order page (but then the re-order page has a significant jump in interface as you loose the tabs):

- We could make another tab, although getting it to show up for a screen-shot is eluding me.

[seth-shaw-unlv]

So I think this is our best option:

HOWEVER, it adds a dependency on islandora_defaults because that is where field_weight is defined. 🙄 So, it looks like I will need to create this as a separate view in islandora_defaults. The question then is how to join them together again. Some funky config edits on the install hook?

[seth-shaw-unlv]

I've updated the PR to just create another tab. It makes the PR much cleaner.

[dannylamb]

Resolved via d45f948