i18n: added dummy file wth translations to help extract JS messages from EE version.

- helps also to translate parts from unreachable code.
  Temp solution, but it works.

rhodecode/public/js/src/i18n_messages.js

@@ -0,0 +1,8 b''
+// special file to catch some of the translation strings NOT extracted by our extraction system
+// we need to fix that, however until now we add here those manual entries to catch them
+
+_gettext('Invite reviewers to this discussion');
+_gettext('Close');
+_gettext('Send');
+_gettext('Switch to chat');
+_gettext('Switch to comment');