re-order users

[Szeraax]

Description

Users are currently displayed in order of entry to the Users table. It is optimal to be able to change the display order. There are 2 ways to set this in the database:

1. order is determined client side and server endpoint just has update order endpoint
2. server has a change user display position endpoint and the logic for moving other users around is contained there

Either option is acceptable for this project, so pick whatever one is cleanest.

Acceptance criteria

• Create a migration to add displayOrder column to users table.
• Add server endpoint for re-ordering users (logic can exist client side or server side)
• Allow admin panel to drag and reorder users like what it does on the Tabs panel with the draggable handle