mail: remove queue proxy

this has never worked well

src/routes/mailserver.js

@@ -65,10 +65,6 @@ async function proxyAndRestart(req, res, next) {
     });
 }
 
-async function queueProxy(req, res, next) {
-    proxyToMailContainer(6000, req.path.replace('/', '/queue/'), req, res, next);
-}
-
 async function getLocation(req, res, next) {
     const [error, result] = await safe(mailServer.getLocation());
     if (error) return next(BoxError.toHttpError(error));
@@ -91,7 +87,6 @@ async function setLocation(req, res, next) {
 export default {
     proxy,
     proxyAndRestart,
-    queueProxy,
 
     setLocation,
     getLocation