Introduce own manager for reduced model object

Move autocomplete functionality to own managers and add functions to
load reduced model objects by id

scm-webapp/src/main/java/sonia/scm/group/DefaultGroupDisplayManager.java

@@ -0,0 +1,25 @@
+package sonia.scm.group;
+
+import sonia.scm.GenericDisplayManager;
+import sonia.scm.search.SearchRequest;
+import sonia.scm.search.SearchUtil;
+
+import javax.inject.Inject;
+
+public class DefaultGroupDisplayManager extends GenericDisplayManager<Group, DisplayGroup> implements GroupDisplayManager {
+
+  @Inject
+  public DefaultGroupDisplayManager(GroupDAO groupDAO) {
+    super(groupDAO, DisplayGroup::from);
+  }
+
+  @Override
+  protected void checkPermission() {
+    GroupPermissions.autocomplete().check();
+  }
+
+  @Override
+  protected boolean matches(SearchRequest searchRequest, Group group) {
+    return SearchUtil.matchesOne(searchRequest, group.getName(), group.getDescription());
+  }
+}