refactor: simplify how url generation works

The URLS file is no longer necessary as urls are now generated directly from the app VHOST file.

This also moves all the url generation logic to the domains plugin.

plugins/domains/functions

@@ -8,12 +8,11 @@ disable_app_vhost() {
   declare desc="disable vhost support for given application"
   declare APP=$1 RESTART_APP="$2"
   local APP_VHOST_PATH="$DOKKU_ROOT/$APP/VHOST"
-  local APP_URLS_PATH="$DOKKU_ROOT/$APP/URLS"
 
   plugn trigger pre-disable-vhost "$APP"
-  if [[ -f "$APP_VHOST_PATH" ]] || [[ -f "$APP_URLS_PATH" ]]; then
+  if [[ -f "$APP_VHOST_PATH" ]]; then
     dokku_log_info1 "App virtual host support disabled"
-    rm -f "$APP_VHOST_PATH" "$APP_URLS_PATH"
+    rm -f "$APP_VHOST_PATH"
   fi
 
   [[ "$RESTART_APP" == "--no-restart" ]] && local CONFIG_SET_ARGS=$RESTART_APP