Refactor less readable inheritance code from CoffeeScript
Child issue of https://gitlab.com/gitlab-org/gitlab-ce/issues/21887
- https://gitlab.com/gitlab-org/gitlab-ce/blob/v8.10.0/app/assets/javascripts/blob/blob_license_selector.js.coffee
- https://gitlab.com/gitlab-org/gitlab-ce/blob/v8.10.0/app/assets/javascripts/blob/blob_ci_yaml.js.coffee
- https://gitlab.com/gitlab-org/gitlab-ce/blob/v8.10.0/app/assets/javascripts/graphs/stat_graph_contributors_graph.js.coffee#L122
- https://gitlab.com/gitlab-org/gitlab-ce/blob/v8.10.0/app/assets/javascripts/graphs/stat_graph_contributors_graph.js.coffee#L122
- https://gitlab.com/gitlab-org/gitlab-ce/blob/v8.10.0/app/assets/javascripts/shortcuts_blob.coffee
- https://gitlab.com/gitlab-org/gitlab-ce/blob/v8.10.0/app/assets/javascripts/shortcuts_dashboard_navigation.js.coffee