[Glitch] [SSR only] Revamp post filtering system

Port CSS and JS for Server-Side Rendered pages from 02851848e9

Signed-off-by: Claire <claire.github-309c@sitedethib.com>

app/javascript/flavours/glitch/packs/settings.js

@@ -2,6 +2,7 @@ import 'packs/public-path';
 import loadPolyfills from 'flavours/glitch/util/load_polyfills';
 import ready from 'flavours/glitch/util/ready';
 import loadKeyboardExtensions from 'flavours/glitch/util/load_keyboard_extensions';
+import 'cocoon-js-vanilla';
 
 function main() {
   const { delegate } = require('@rails/ujs');