Merge branch 'hly-performance-bar-lazy' into 'master'

...cripts/performance_bar/components/performance_bar_app.vue

...vascripts/performance_bar/components/request_selector.vue

app/assets/javascripts/performance_bar/index.js

...vascripts/performance_bar/stores/performance_bar_store.js

...formance/img/performance_bar_request_selector_warning.png

doc/administration/monitoring/performance/performance_bar.md

locale/gitlab.pot

...nd/performance_bar/components/performance_bar_app_spec.js

...ntend/performance_bar/components/request_selector_spec.js

spec/frontend/performance_bar/index_spec.js