JpaDistributionSet#metadata made Map (#2411)

Signed-off-by: Avgustin Marinov <Avgustin.Marinov@bosch.com>

hawkbit-core/src/main/java/org/eclipse/hawkbit/repository/DistributionSetMetadataFields.java

@@ -1,33 +0,0 @@
-/**
- * Copyright (c) 2015 Bosch Software Innovations GmbH and others
- *
- * This program and the accompanying materials are made
- * available under the terms of the Eclipse Public License 2.0
- * which is available at https://www.eclipse.org/legal/epl-2.0/
- *
- * SPDX-License-Identifier: EPL-2.0
- */
-package org.eclipse.hawkbit.repository;
-
-import lombok.Getter;
-
-/**
- * Sort fields for DistributionSetMetadata.
- */
-@Getter
-public enum DistributionSetMetadataFields implements RsqlQueryField {
-
-    KEY("key"),
-    VALUE("value");
-
-    private final String jpaEntityFieldName;
-
-    DistributionSetMetadataFields(final String jpaEntityFieldName) {
-        this.jpaEntityFieldName = jpaEntityFieldName;
-    }
-
-    @Override
-    public String identifierFieldName() {
-        return KEY.getJpaEntityFieldName();
-    }
-}