[Docker] Build webpack bundles at build time

Dockerfile

@@ -73,6 +73,8 @@ CMD ["/usr/local/bin/aleksis-docker-startup"]
 # Install assets
 FROM core as assets
 RUN eatmydata aleksis-admin yarn install; \
+    eatmydata aleksis-admin write_webpack_entrypoints; \
+    yarn run webpack; \
     eatmydata aleksis-admin collectstatic --no-input; \
     rm -rf /usr/local/share/.cache
 
@@ -119,6 +121,8 @@ ONBUILD RUN set -e; \
                 eatmydata pip install $APPS; \
             fi; \
             eatmydata aleksis-admin yarn install; \
+            eatmydata aleksis-admin write_webpack_entrypoints; \
+            yarn run webpack; \
             eatmydata aleksis-admin collectstatic --no-input; \
             rm -rf /usr/local/share/.cache; \
             eatmydata apt-get remove --purge -y yarnpkg $BUILD_DEPS; \