change site docker build to proper two-stage with repoxy to serve content

site/Dockerfile

@@ -1,4 +1,4 @@
-FROM node:16-alpine
+FROM node:16-alpine as build
 
 WORKDIR /site
 COPY ./ /site
@@ -6,3 +6,8 @@ RUN yarn --frozen-lockfile
 
 CMD yarn build
 
+FROM ghcr.io/umputun/reproxy
+COPY --from=build /site/build /srv/site
+EXPOSE 8080
+USER app
+ENTRYPOINT ["/srv/reproxy", "--assets.location=/srv/site"]