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/misc/file_manager/static/js/select_dialogue.js

@@ -22,7 +22,7 @@ module.exports =  Alertify.dialog('fileSelectionDlg', function() {
       // Set title and button name
       var self = this;
       if (_.isUndefined(params['dialog_title'])) {
-        params['dialog_title'] = 'Select file';
+        params['dialog_title'] = gettext('Select file');
       }
       self.dialog_type = params['dialog_type'];