Updates pipeline code to use gitlab-ui

...vascripts/pipelines/components/graph/action_component.vue

...scripts/pipelines/components/graph/job_group_dropdown.vue

...ssets/javascripts/pipelines/components/graph/job_item.vue

...pts/pipelines/components/graph/stage_column_component.vue

.../javascripts/pipelines/components/pipelines_table_row.vue

app/assets/javascripts/pipelines/components/stage.vue

spec/javascripts/pipelines/graph/job_item_spec.js