[Elasticsearch] More efficient search
We should filter items by querying it in filter scope rather than in query scope as we don't need any scoring when filter by project.
Also fixes part of https://gitlab.com/gitlab-org/gitlab-ee/issues/1776
We should filter items by querying it in filter scope rather than in query scope as we don't need any scoring when filter by project.
Also fixes part of https://gitlab.com/gitlab-org/gitlab-ee/issues/1776