Add conditional importmap installation in Dockerfile

Author: florentdestremau

Dockerfile

@@ -93,3 +93,9 @@ RUN set -eux; \
 	composer dump-env prod; \
 	composer run-script --no-dev post-install-cmd; \
 	chmod +x bin/console; sync;
+
+RUN if [ -f importmap.php ]; then \
+    php bin/console importmap:install;\
+    php bin/console asset-map:compile;\
+fi
+