authn: Fix form validation of authentication plugins. - Check if plugin exists. - Display an apropriate error message if it doesn't exist.

admin: tweak usergroup settings ui for clarity

permissions: show overridden permissions in permission summary page

auth-token: added missing renderers for token plugin

cleanup: remove couple overlooked lines

cleanup: rename class name

cleanup: remove duplicate route

cleanup: move jsroutes generator function and only generate in debug mode

refactor: made javascript routes autogenerate based on python routes

admin: in usergroups admin allow prefiltering the list of users based on an autocomplete query. also updated a couple tests which were not testing correct response.