Create a Work items relationship widget shell

...items/components/shared/work_item_link_child_contents.vue

...ts/javascripts/work_items/components/work_item_detail.vue

...items/components/work_item_links/work_item_link_child.vue

...nents/work_item_relationships/work_item_relationships.vue

app/assets/javascripts/work_items/constants.js

...pts/work_items/graphql/work_item_widgets.fragment.graphql

app/assets/javascripts/work_items/utils.js

app/controllers/projects/incidents_controller.rb

app/controllers/projects/issues_controller.rb

app/controllers/projects/work_items_controller.rb

app/controllers/projects_controller.rb

...pts/work_items/graphql/work_item_widgets.fragment.graphql

ee/spec/features/projects/work_items/okr_spec.rb

locale/gitlab.pot

...s/components/work_item_links/work_item_link_child_spec.js

...s/work_item_relationships/work_item_relationships_spec.js

spec/frontend/work_items/utils_spec.js