Add "we won't do this" as a reason to close an issue
/cc @gl-product
The idea here is some issues we should close because we know we won't do them. This includes issues that are hard to close because they are popular (e.g. https://gitlab.com/gitlab-org/gitlab-ce/issues/12736#note_50662947) or issues that we've intentionally architected the opposite way (e.g. https://gitlab.com/gitlab-org/gitlab-ce/issues/43251)
From Slack conversation: https://gitlab.slack.com/archives/C0NFPSFA8/p1545063494350600