formatting: bulk remove trailing whitespaces

Do not touch vendorized files (e.g. libraries that were imported from external
projects).

No functional changes.

Command:
    find . -name '*.<EXTENSION>' -type f -print0 | xargs -0 sed -i 's/[[:space:]]*$//'

src/node/db/Pad.js

@@ -460,7 +460,7 @@ Pad.prototype.remove = async function remove() {
   // none of the operations except getting the group depended on callbacks
   // so the database operations here are just started and then left to
   // run to completion
- 
+
   // is it a group pad? -> delete the entry of this pad in the group
   if (padID.indexOf("$") >= 0) {
 

src/node/hooks/i18n.js

@@ -39,7 +39,7 @@ function getAllLocales() {
 
   //add core supported languages first
   extractLangs(npm.root+"/ep_etherpad-lite/locales");
-  
+
   //add plugins languages (if any)
   for(var pluginName in plugins) extractLangs(path.join(npm.root, pluginName, 'locales'));
 
@@ -94,11 +94,11 @@ exports.expressCreateServer = function(n, args) {
       res.status(404).send('Language not available');
     }
   })
-  
+
   args.app.get('/locales.json', function(req, res) {
     res.setHeader('Content-Type', 'application/json; charset=utf-8');
     res.send(localeIndex);
   })
-  
+
 }