Fix gradle methods to actually first build frontend

Some spring tasks were sometimes doing bootJar (spring's own jar building) before my copy dependency. This new method should work for all ways of running the server (build, assemble, bootRun).

.gitlab-ci.yml

@@ -2,4 +2,4 @@ image: gradle:4.7-jdk8
 
 backend:
     script:
-        gradle check
+        gradle check -Ddownload-node=true