Scope on User to filter by role

https://www.agileplannerapp.com/boards/173808/cards/4223

working on a filter by role functionality on the users
index page. these are related model changes to enable
that.
Controller changes to filter users by role

also, a few improvements to tests related to filtering.
Adding link to users index for filtering by role

also, fixed the 'Clear' button which was not clearing
the query params as expected.
Integration test for filter by role
Styling for filter panel
Update title & menu label to indicate role filter
Non-JS version of filter by role
Display list of roles sorted by level
Merge pull request #243 from alphagov/filter-by-role

Filter by role
Set autofocus on input field

As a superadmin
When I am adding a new permission
I would like the focus to be on the input field
So that I can start to type without tabbing or clicking
Merge pull request #250 from alphagov/feature/add-permission-autofocus

Set autofocus on input field
Fix title on user edit page

Without this, the page title is:

<title>Edit &amp;quot;<name>&amp;quot; | GOV.UK Signon</title>
Merge pull request #251 from alphagov/fix-title-on-user-edit-page

Fix title on user edit page
API user list, create, and edit actions

1. separate ApiUser class allows us to configure
   cancan abilities better.
2. re-using suspension actions, just redirecting
   back to the correct edit page.
3. added the table name to Doorkeeper::Application
   default_scope otherwise there's an abiguous name
   column during a table join.
4. hiding "Has access?" column in the permissions
   grid on api user's edit page, in favor of the
   Tokens table and assigning 'signin' permission
   by default whenever token is generated for an
   application.
5. templates by Paul H.
Manage API user access tokens

1. using zeroclipboard library for 'Copy to clipboard'
   button for access tokens.
2. fixed n+1 issues in UserPermissionsControllerMethods
   by performing some grouping operations in Ruby.
Integration test for managing API users
Feedback on PR

1. removed inline styles.
2. added a generated at timestamp to tokens table.
Event log entries for API user events