onlyoffice previews much faster and more robust, added --oosetup helper, improved error/log handling

docker/onlyoffice-converter-patch/entrypoint.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+# Custom entrypoint that persists WORKERS to a file readable by
+# the non-root user that supervisor uses to run the converter.
+
+echo "${WORKERS:-8}" > /tmp/oo-converter-workers.txt
+chmod 644 /tmp/oo-converter-workers.txt
+
+exec /app/ds/run-document-server.sh "$@"