Port 'Add more usage data to EE ping' to CE

app/assets/javascripts/application_settings.js.es6

app/assets/javascripts/dispatcher.js

app/controllers/admin/application_settings_controller.rb

app/views/admin/application_settings/_form.html.haml

app/workers/gitlab_usage_ping_worker.rb

config/routes/admin.rb

lib/gitlab/usage_data.rb

...controllers/admin/application_settings_controller_spec.rb

spec/lib/gitlab/usage_data_spec.rb

spec/workers/gitlab_usage_ping_worker_spec.rb