Add editable title and description

...vascripts/work_items/components/work_item_description.vue

.../work_items/components/work_item_description_rendered.vue

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

...ripts/work_items/components/work_item_title_with_edit.vue

app/assets/stylesheets/page_bundles/work_items.scss

...k_items/components/work_item_description_rendered_spec.js

...ntend/work_items/components/work_item_description_spec.js

spec/frontend/work_items/components/work_item_detail_spec.js

...d/work_items/components/work_item_with_title_edit_spec.js

...rt/shared_examples/features/work_items_shared_examples.rb