refactor(core): remove GA page views report (#1071)

- Google Analytics superProxy has been archived and is no longer maintained.
- Google Analytics UA end of life.

See also: https://support.google.com/analytics/answer/11583528?hl=en

_javascript/modules/plugins.js

@@ -3,5 +3,4 @@ export { initClipboard } from './components/clipboard';
 export { imgLazy } from './components/img-lazyload';
 export { imgPopup } from './components/img-popup';
 export { initLocaleDatetime } from './components/locale-datetime';
-export { initPageviews } from './components/pageviews';
 export { toc } from './components/toc';