Fixed gettext usage:

- fixed gettext usage with .format() only for original text with %s
  - fixed typos
  - fixed translation yes/no buttons in the dialog.
  - improved translating sentences without "connecting" words (eg. see web/pgadmin/dashboard/static/js/dashboard.js,
     word 'cancel' needs to be translated in the Czech language as 'zrušit' but in another sentence as 'zrušení')
  - added gettext for text translations.

web/pgadmin/tools/backup/static/js/backup_dialog.js

@@ -15,7 +15,7 @@ import axios from 'axios/index';
 
 export class BackupDialog extends Dialog {
   constructor(pgBrowser, $, alertify, BackupModel, backform = Backform) {
-    super('Backup Error',
+    super(gettext('Backup Error'),
       '<div class=\'backup_dialog\'></div>',
       pgBrowser, $, alertify, BackupModel, backform
     );