fix(healthcheck): use address configured if not empty

1. Use `$FB_ADDRESS` content if not empty;
2. Fallback on "address" value in /.filebrowser.json
3. Fallback on `localhost`

healthcheck.sh

@@ -1,3 +1,5 @@
 #!/bin/sh
 PORT=${FB_PORT:-$(jq .port /.filebrowser.json)}
-curl -f http://localhost:$PORT/health || exit 1
+ADDRESS=${FB_ADDRESS:-$(jq .address /.filebrowser.json)}
+ADDRESS=${ADDRESS:-localhost}
+curl -f http://$ADDRESS:$PORT/health || exit 1