Decouple auto assign check (#1000)

* Introduce auto assign executer interface to override check method.
* Add copyright header.
* Move documentation to interface. Annotate the AutoAssignExecutor as FunctionalInterface.
* Rename method to match interface name

Signed-off-by: Michael Herdt <Michael.Herdt2@bosch-si.com>

hawkbit-repository/hawkbit-repository-api/src/main/java/org/eclipse/hawkbit/repository/autoassign/AutoAssignExecutor.java

@@ -0,0 +1,25 @@
+/**
+ * Copyright (c) 2020 Bosch.IO GmbH and others.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.eclipse.hawkbit.repository.autoassign;
+
+/**
+ * An interface declaration which contains the check for the auto assignment
+ * logic.
+ */
+@FunctionalInterface
+public interface AutoAssignExecutor {
+
+    /**
+     * Checks all target filter queries with an auto assign distribution set and
+     * triggers the check and assignment to targets that don't have the design DS
+     * yet
+     */
+    void check();
+
+}