This refactors the AutocompleteController according to the guidelines and boundaries discussed in https://gitlab.com/gitlab-org/gitlab-ce/issues/49653. Specifically, ActiveRecord logic is moved to different finders, which are then used in the controller. View logic in turn is moved to presenters, instead of directly using ActiveRecord's "to_json" method. The finder MoveToProjectFinder is also adjusted according to the abstraction guidelines and boundaries, resulting in a much more simple finder. By using finders (and other abstractions) more actively, we can push a lot of logic out of the controller. We also remove the need for various "before_action" hooks, though this could be achieved without using finders as well. The various finders related to AutcompleteController have also been moved into a namespace. This removes the need for calling everything "AutocompleteSmurfFinder", instead you can use "Autocomplete::SmurfFinder".