Deprecate redundant APIs

This commit deprecates redundant APIs to simplify the way to
configure and use Spring Batch. The most notable changes are:

- JobLauncher is deprecated in favor of JobOperator
- JobExplorer is deprecated in favor of JobRepository
- CommandLineJobRunner is deprecated in favor of more
modern alternatives like Spring Boot's job Launcher

Other APIs that are only used in the newly deprecated APIs
have been deprecated as well.

Resolves #4847

spring-batch-infrastructure/src/main/java/org/springframework/batch/support/PropertiesConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2023 the original author or authors.
+ * Copyright 2006-2025 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.
@@ -32,7 +32,10 @@ import org.springframework.util.StringUtils;
  * @author Lucas Ward
  * @author Dave Syer
  * @author Mahmoud Ben Hassine
+ *
+ * @deprecated since 6.0 with no replacement. Scheduled for removal in 6.2 or later.
  */
+@Deprecated(since = "6.0", forRemoval = true)
 public final class PropertiesConverter {
 
 	private static final String LINE_SEPARATOR = "\n";