syslog: change it to unix domain socket

docker is using a extra udp port for every container. when there is
a lot of containers, a lot of random udp ports get used up. this causes
problems when installing apps that require contiguous port ranges

src/apps.js

@@ -218,7 +218,6 @@ function validatePortBindings(portBindings, manifest) {
         993, /* imaps */
         995, /* pop3s */
         2003, /* graphite (lo) */
-        2514, /* cloudron-syslog (lo) */
         constants.PORT, /* app server (lo) */
         constants.AUTHWALL_PORT, /* protected sites */
         constants.INTERNAL_SMTP_PORT, /* internal smtp port (lo) */