copied and adjusted some existing images to be built for riscv, used debian:unstable as base as it has a riscv image available
UNTESTED, POTENTIALLY UNSTABLE, NO SUPPORT PROVIDED, USE AT OWN RISK
adjusted from https://github.com/nodejs/docker-node/tree/main/18/buster
using https://unofficial-builds.nodejs.org/ riscv build
published to thepiwo/node:18-debian-unstable
somewhat trivial implementation, not sure if that's sufficient
published to thepiwo/nginx:debian-unstable