Remove deprecations/cleanup

- Remove deprecated AbstractChatMemoryAdvisor#DEFAULT_CHAT_MEMORY_CONVERSATION_ID
 - Remove deprecated InMemoryChatMemory and replace it with MessageWindowChatMemory
   - Update references

 - Remove deprecated TemplateFormat

Signed-off-by: Ilayaperumal Gopinathan <ilayaperumal.gopinathan@broadcom.com>

spring-ai-model/src/main/java/org/springframework/ai/chat/prompt/TemplateFormat.java

@@ -1,48 +0,0 @@
-/*
- * Copyright 2023-2025 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.chat.prompt;
-
-import org.springframework.ai.template.TemplateRenderer;
-
-/**
- * @deprecated in favor of {@link TemplateRenderer}.
- */
-@Deprecated
-public enum TemplateFormat {
-
-	ST("ST");
-
-	private final String value;
-
-	TemplateFormat(String value) {
-		this.value = value;
-	}
-
-	public static TemplateFormat fromValue(String value) {
-		for (TemplateFormat templateFormat : TemplateFormat.values()) {
-			if (templateFormat.getValue().equals(value)) {
-				return templateFormat;
-			}
-		}
-		throw new IllegalArgumentException("Invalid TemplateFormat value: " + value);
-	}
-
-	public String getValue() {
-		return this.value;
-	}
-
-}