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- Google Analytics superProxy has been archived and is no longer maintained.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/post.js

@@ -4,7 +4,6 @@ import {
   imgPopup,
   initLocaleDatetime,
   initClipboard,
-  initPageviews,
   toc
 } from './modules/plugins';
 
@@ -16,4 +15,3 @@ imgPopup();
 initLocaleDatetime();
 initClipboard();
 toc();
-initPageviews();