Configure gateway limits and encrypted storage

.env.example

@@ -13,3 +13,9 @@ PUBLIC_BYTES_PER_SECOND=0
 PUBLIC_BYTE_BURST=
 PUBLIC_MAX_IN_FLIGHT_PER_IP=
 PUBLIC_TRUSTED_PROXY_IPS=
+MAX_IN_FLIGHT_REQUESTS=16
+HTTP_BACKLOG=64
+S3_VIRTUAL_HOST_SUFFIX=
+# For compose.encrypted.yaml only; provision and mount LUKS before setting these.
+ENCRYPTED_STORAGE_ROOT=
+ENCRYPTED_VOLUME_ID=