Fixes #8424 - Controller concerns are loaded twice

config/application.rb, we are adding the controller concerns twice
folder to autoload_paths
Fixes #4613 - Remove duplicate scoped search from taxonomies
Fixes #8425 - n+1 query on audits index

Audits index include users who performed actions, and these are being
called with n+1 queries. Fix should be as simple as providing the
users through the controller with an includes.