Replace glitch-soc's collapsed toots with upstream's “Read more” (#2916)

* Remove glitch-soc's post collapse feature

* Get rid of the infamous `parseClick`

* Remove unused CSS

* Use upstream's “Read More” implementation

* Update translation strings

app/javascript/flavours/glitch/features/ui/index.jsx

@@ -132,7 +132,6 @@ const keyMap = {
   goToRequests: 'g r',
   toggleHidden: 'x',
   bookmark: 'd',
-  toggleCollapse: 'shift+x',
   toggleSensitive: 'h',
   openMedia: 'e',
 };