add: merge frontend with backend static

Dockerfile-mergefront

@@ -0,0 +1,19 @@
+FROM node:16 as builder
+ARG VITE_API_URL
+ARG VITE_KEYCLOAK_CLIENT_ID
+ARG VITE_KEYCLOAK_CLIENT_SECRET
+ARG VITE_KEYCLOAK_URL
+WORKDIR /usr/src/postamates_frontend
+ENV NODE_OPTIONS=--max_old_space_size=4096
+COPY package*.json ./
+COPY yarn.lock ./
+RUN yarn install
+COPY . .
+RUN yarn build
+
+FROM scratch AS host-export
+COPY --from=builder /usr/src/postamates_frontend/dist .
+# first create dist directory to avoid overstrict permissions
+# mkdir ../dist
+# then compile the result into that directory using buildkit
+# DOCKER_BUILDKIT=1 docker build --file Dockerfile-mergefront --output ../dist .