Add javadoc about what is DbSettingConfigHelper. IQSS#7457

src/main/java/edu/harvard/iq/dataverse/settings/source/DbSettingConfigHelper.java

@@ -7,6 +7,13 @@
 import javax.ejb.Singleton;
 import javax.ejb.Startup;
 
+/**
+ * This is a small helper bean for the MPCONFIG DbSettingConfigSource.
+ * As it is a singleton and built at application start (=deployment), it will inject the (stateless)
+ * settings service into the MPCONFIG POJO once it's ready.
+ *
+ * MPCONFIG requires it's sources to be POJOs. No direct dependency injection possible.
+ */
 @Singleton
 @Startup
 public class DbSettingConfigHelper {