Remove duplicated ApiUtils and polish javadocs

spring-ai-core/src/main/java/org/springframework/ai/util/api/ApiUtils.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2023 - 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.ai.util.api;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
+
+import java.util.function.Consumer;
+
+/**
+ * The ApiUtils class provides utility methods for working with API requests and
+ * responses.
+ *
+ * @author Geng Rong
+ * @author Christian Tzolov
+ * @author Piotr Olaszewski
+ * @since 1.0.0 M1
+ */
+public class ApiUtils {
+
+	public static Consumer<HttpHeaders> getJsonContentHeaders(String apiKey) {
+		return (headers) -> {
+			headers.setBearerAuth(apiKey);
+			headers.setContentType(MediaType.APPLICATION_JSON);
+		};
+	}
+
+}