add capability to restrict remote panel modes

Dockerfile

@@ -18,6 +18,7 @@ FROM scratch
 # Group ID 20 is dialout, needed for tty read/write access
 USER 3000:20
 ENV READ_ONLY=false
+ENV CONTROL_ALLOWED_PANEL_MODES=""
 COPY --from=builder /build/invertergui /bin/
 ENTRYPOINT [ "/bin/invertergui" ]
 EXPOSE 8080