[ci skip] Remove loadscript class in favour of backend conditional

app/assets/javascripts/application.js

app/assets/javascripts/lib/utils/load_script.js.es6

app/assets/javascripts/raven/index.js

app/assets/javascripts/raven/raven_config.js

app/assets/javascripts/raven_config.js.es6

app/helpers/sentry_helper.rb

app/views/layouts/application.html.haml

app/views/layouts/devise.html.haml

app/views/layouts/devise_empty.html.haml

config/webpack.config.js

lib/gitlab/gon_helper.rb

package.json

spec/features/raven_js_spec.rb

spec/javascripts/class_spec_helper.js.es6

spec/javascripts/class_spec_helper_spec.js.es6

spec/javascripts/lib/utils/load_script_spec.js.es6

spec/javascripts/raven/index_spec.js

spec/javascripts/raven/raven_config_spec.js

vendor/assets/javascripts/raven.js

yarn.lock