Look into using a better component for the admin Queues table

[jonespm]

If you have a lot of users on your system, when looking at a Queue in the admin view it the select element for Hosts isn't very usable.

To reproduce

1. On a system with a lot of users (100+?), and at least 1 queue, login to ROHQ as to /admin as admin and select Queues
2. Select a Queue by ID it shows a Hosts select box with a ton of users.

This makes it hard to see who the Host(s) are if there's more than one.

We should look into replacing this with some other type of element. It looks like there's two built in that could work to make it more obvious who are selected. I believe this is the same thing used on the Groups page.

https://docs.djangoproject.com/en/dev/ref/contrib/admin/#django.contrib.admin.ModelAdmin.filter_horizontal