On the Diffusion cluster status page, improve device sort order

Summary:
Ref T13216. See PHI943. When you have a large number of cluster bindings for a repository, the UI sorting can be a bit hard to manage.

One install that regularly cycles repository cluster devices had a couple dozen older disabled bindings, with the enabled bindings intermingled.

Sort the UI:

• enabled devices come first;
• in each group, sort by name.

Test Plan: Mixed disabled/enabled bindings, loaded Diffusion → Repository → Storage page with clustering configured. Before: relatively unhelpful sort order. After: more intuitive sort order.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13216

Differential Revision: https://secure.phabricator.com/D19813