Deprecate org.apache.maven.repository.RepositorySystem in 3.9.x

As we have only legacy implementation and use many other staff that is already deprecated.

Author: slawekjaranowski

maven-core/src/main/java/org/apache/maven/repository/RepositorySystem.java

@@ -38,7 +38,10 @@
 /**
  * @author Jason van Zyl
  * @since 3.0-alpha
+ *
+ * @deprecated Use maven-resolver and new DefaultArtifact(...) directly instead.
  */
+@Deprecated
 public interface RepositorySystem {
     String DEFAULT_LOCAL_REPO_ID = "local";