refactor: deprecate proxy-configure-ports plugin trigger in favor of ports-configure

This also rewrites the logic to be in golang, which will make it easier to refactor portions of it to use the property system going forward.

plugins/nginx-vhosts/functions

@@ -318,7 +318,7 @@ nginx_build_config() {
     fi
 
     # setup nginx listen ports
-    plugn trigger proxy-configure-ports "$APP"
+    plugn trigger ports-configure "$APP"
     local PROXY_PORT=$(config_get "$APP" DOKKU_PROXY_PORT)
     local PROXY_SSL_PORT=$(config_get "$APP" DOKKU_PROXY_SSL_PORT)
     local PROXY_PORT_MAP=$(plugn trigger ports-get "$APP")