Refactor the production Docker image

tools/docker/images/Dockerfile

@@ -0,0 +1,21 @@
+FROM opdavies/sculpin-serve AS app
+WORKDIR /app
+COPY composer.* ./
+RUN composer install
+COPY app app
+COPY source source
+RUN sculpin generate -e prod
+
+FROM node:14 AS assets
+WORKDIR /node
+COPY package.json .
+COPY package-lock.json .
+RUN npm ci
+COPY . .
+RUN npm run production
+
+FROM nginx AS nginx
+COPY tools/docker/images/nginx/root /
+WORKDIR /app
+COPY --from=app /app/output_prod ./
+COPY --from=assets /node/source/build build