Promote language choice to page heading

This commit moves the language choice part of the form from the
"advanced" section to the main heading.

See gh-432

initializr-service/src/main/resources/application.yml

@@ -1148,12 +1148,12 @@ initializr:
     - name: Java
       id: java
       default: true
-    - name: Groovy
-      id: groovy
-      default: false
     - name: Kotlin
       id: kotlin
       default: false
+    - name: Groovy
+      id: groovy
+      default: false
   bootVersions:
     - name : Latest SNAPSHOT
       id: 1.2.4.BUILD-SNAPSHOT